by P. D. Smith
What might these two refugee scientists have said to each other if they had met while walking through the neatly manicured gardens of Russell Square, just outside their hotels? The Nobel prizewinning chemist Fritz Haber was at the end of his career, had been disowned by his country and thrown out of the institute he founded, and now had just a few months to live. Every few steps, he had to pause and catch his breath. He was a shadow of the dynamic man he had once been. By contrast, Leo Szilard, the budding nuclear physicist, was 35 years old, his figure still slim and youthful. He would have been striding past the London plane trees in the square, perhaps on his way to see his and Haber’s mutual friend, Professor Donnan at UCL. For Donnan – who was active on behalf of the AAC– had also offered Leo Szilard a job.
Szilard came with the best possible references from some of the greatest physicists of the age, including Einstein, Max von Laue and Schrödinger. Even Faust had recommended him. Paul Ehrenfest (aka Faust in the Copenhagen performance) had sent Donnan a warm personal testament: ‘Szilard is a very rare example of a man, because of his combination of great purely scientific acumen, his ability to immerse himself in and solve technical problems, his fascination and fantasy for organizing, and his great sensitivity and compassion for people in need.’19 Tragically, within weeks of writing this letter of recommendation, Ehrenfest committed suicide. According to the note he left, one of his reasons was that he was in despair at the incomprehensible quantum realm.
That summer, London was brimming with brilliant scientists and other intellectuals fleeing Hitler’s Germany. Among them was another future doomsday man – Edward Teller. He also visited Frederick Donnan at University College to discuss the possibility of a job, and Donnan arranged for him to spend a year with the other budding Fausts at Bohr’s Institute. Typically, Leo Szilard couldn’t make up his mind whether to accept Donnan’s offer of a position at UCL. In any case, he was too busy saving Germany’s other forsaken intellectuals.
At the beginning of November, Fritz Haber was back in London, staying in the same hotel on Russell Square. His visit in July had paid off. Haber’s British friends in chemical warfare, Sir Harold Hartley and Sir William Pope, had secured a position for him at Cambridge University, where he would be free to continue his research. Ten years earlier, Ernest Rutherford had refused to shake Haber’s hand when he visited Cambridge. Now the University welcomed their country’s former enemy and asked him to stay as long as he wished.
At Cambridge, Haber was visited by fellow refugee scientists, including Max Born and Michael Polanyi, the latter having finally taken Szilard’s advice and accepted the position at Manchester University. Born recalls that Haber appeared ‘ill, depressed, lonely, a shadow of his former self’. When he tried to arrange a meeting between Haber and Rutherford, the physicist again refused, ‘saying frankly that he did not want to shake hands with the inventor of poison gas warfare’.20 After just two months in Cambridge, Haber’s health worsened, partly because of the damp English weather. He moved to Switzerland to recuperate, but died in Basel at the end of January 1934.21
When Edward Teller returned from Copenhagen in the autumn of that year, a job was waiting for him in the chemistry department of UCL. Before formally offering Teller the position, Donnan insisted that he complete some essential background reading: Lewis Carroll’s Alice’s Adventures in Wonderland and Through the Looking-Glass. ‘He did not want to import a barbarian into England,’ recalled Teller.22 But in the New Year, the 26-year-old physicist received two job offers from America. One was from Eugene Wigner, who wanted Teller to join him and the other member of the Hungarian Quartet, John von Neumann, at Princeton. The other was from George Washington University, where his friend George Gamow was chairman of the physics department. This last offer was too tempting to decline. But the father of the hydrogen bomb never forgot the generosity of the English. They were, he said, ‘truly among the most hospitable and ethical people in the world’.23
Leo Szilard was also fond of England. The reserve of the natives suited his own essentially shy character, and he felt a deep sympathy with the country and its people. But, he added shrewdly, ‘I am not yet sure about the sympathy being mutual.’24
Throughout 1933, Szilard worked tirelessly and selflessly on behalf of his fellow refugee academics. The money he had earned from his patents, including the refrigerator designs, allowed him to live without financial worries, for the time being at least. His daily routine at the Imperial Hotel began with breakfast in the plush restaurant, followed by a leisurely and extended soak in a bath – the only luxury the decidedly non-materialistic Szilard permitted himself. It was not uncommon for him to spend three hours in a tub, awaiting Archimedean inspiration. However, it was not in the bath that Leo Szilard had his Eureka! moment in 1933, but on a Bloomsbury street.
‘The passage of the invisible neutron into the nucleus of the atom is like an invisible man passing through Piccadilly Circus: His path can be traced only by the people he has pushed aside.’25 This was the wonderful image Lord Rutherford used in 1932 to describe the effect of the neutron on the atom. The following year, he surveyed the astonishing progress that had been made in ‘breaking down the atom’. Speaking to colleagues at the British Association’s conference in Leicester, he outlined how James Chadwick’s ‘most remarkable’ neutron could be used as a tool of transmutation, for instance changing oxygen into carbon.26 The subatomic invisible man could pass freely through atoms, thanks to its lack of an electrical charge. It could even enter the dark heart of matter, the nucleus.
As a purist, Ernest Rutherford had little interest in the potential applications of science. He wanted to understand how ‘the nuclei of atoms were made’, not how to release the energy of the atom. According to David Wilson, Rutherford’s biographer, ‘his lack of imagination in translating the results of his work from the laboratory to the outside world of technology, profit and commerce’ was a serious failing.27 So when Rutherford allowed himself the luxury of anticipating what advances might lie twenty or thirty years ahead, he was scathing about the chances of releasing atomic energy. Certainly, he told his audience at the British Association conference in 1933, scientists would use increasingly powerful particle accelerators – such as his colleagues Cockcroft and Watson had built – to smash apart the stuff of matter. But, ever keen to nip sensationalist press stories in the bud, Rutherford rejected the idea that proton accelerators could be used to generate power:
We might in these processes obtain very much more energy than the proton supplied, but on the average we could not expect to obtain energy in this way. It was a very poor and inefficient way of producing energy, and anyone who looked for a source of power in the transformation of the atoms was talking moonshine.28
Moonshine!
Leo Szilard frowned as he read the word, late on the morning of Tuesday 12 September 1933, and glanced around the lobby of the Imperial Hotel, as if he expected the concierge to share his consternation. Moonshine… He muttered the word under his breath. If there was one thing in science that really made Szilard angry, it was experts who said that something was impossible. He looked back at the long article on page 7 of that day’s Times. The paper had devoted two of its lead columns to the British Association conference, and Rutherford’s speech on transmuting the atom was reported almost word for word.
Leo Szilard was anything but a purist when it came to science. In the right hands, science could transform the world. In the wrong hands, it just might destroy it. Szilard folded his paper and looked out through the lobby window to Russell Square, where the leaves of the plane trees were just beginning to turn gold in anticipation of autumn. He needed to think. So, as he had done in Berlin a decade ago, when he was trying to conjure up an original idea for his thesis, Szilard took to his feet. He left the hotel lobby and set off into the grey light of an overcast September day.
Many years later in America, Szilard would recall this moment, as he walked the streets of London, pondering subatomic phy
sics and Rutherford’s comments to the great and the good of British science. ‘I remember that I stopped for a red light at the intersection of Southampton Row.’29 The London traffic streamed by, but he scarcely noticed the vehicles. Instead, in his mind he saw streams of subatomic particles bombarding atoms.
As the traffic lights changed and the cars stopped, the physicist stepped out in front of the impatient traffic. A keen-eyed London cabby, watching Szilard cross the road, might have noticed him pause for a moment in the middle. Szilard may even have briefly raised his hand to his forehead, as if to catch hold of the beautiful but terrible thought that had just crossed his mind. But that taxi driver could have no inkling of the gravity of the moment, even though it would affect the course of both his life and the lives of his children. For that was when Leo Szilard saw precisely how to release the energy locked up in the heart of every atom, a self-sustaining chain reaction created by neutrons:
As I was waiting for the light to change and as the light changed to green and I crossed the street, it suddenly occurred to me that if we could find an element which is split by neutrons and which would emit two neutrons when it absorbed one neutron, such an element, if assembled in sufficiently large mass, could sustain a nuclear chain reaction. I didn’t see at the moment just how one would go about finding such an element, or what experiments would be needed, but the idea never left me. In certain circumstances it might become possible to set up a nuclear chain reaction, liberate energy on an industrial scale, and construct atomic bombs. The thought that this might be in fact possible became a sort of obsession with me.30
In his lecture, Rutherford had described how the neutron ‘could go freely through atoms, and had a good chance of entering the nucleus and of either disturbing or being captured by the nucleus’.31 But what Szilard had just realized, before anyone else, was that the reaction might not terminate in a single nucleus – it could spread, explosively. As if anticipating this dangerous idea, the sceptical Rutherford promptly poured cold water over it in a BBC radio lecture one month later. Indeed, Szilard may have listened to it at the Imperial Hotel. If he didn’t, then he certainly saw the reports on it in the following day’s Times.
‘It has sometimes been suggested,’ said Rutherford in the lecture, ‘from analogy with ordinary explosives, that the transmutation of one atom might cause the transmutation of a neighbouring nucleus, so that the explosion would spread throughout all the material. If that were true, we should long ago have had a gigantic explosion in our laboratories with no one remaining to tell the tale.’32 The ‘explosion’ in a single atom, he emphasized, does not ‘spread to the neighbouring nuclei’. But this is precisely what Leo Szilard had decided could happen. Hearing Britain’s leading Nobel prizewinning physicist declare it was impossible only made him more convinced that he was on the right track. After all, what did these experts know?
Szilard would spend the next decade of his life trying to convince others that he was right. He even tried to convince Lord Rutherford, an act of unforgivable chutzpah which earned Szilard the distinction of being the only person to be thrown out of the physicist’s Cambridge office. It was clearly going to be an uphill struggle.
The scientist and writer Jacob Bronowski said that there was only one part of his friend’s story of the Eureka! moment near Russell Square that he found improbable: ‘I never knew Szilard to stop for a red light.’33 Did the idea of a nuclear chain reaction come to him in one dazzling epiphany? This is what Szilard said almost thirty years later. But memories are not always reliable, and he liked a good story. Perhaps the idea of the chain reaction grew gradually over countless walks around Bloomsbury that autumn, as he pondered the provocative statements of the undisputed master of the nucleus, Ernest Rutherford.
One thing we do know, however, is that as he hatched his explosive idea about how to release atomic energy, Szilard was also thinking about The World Set Free. A few days after he put the finishing touches to his first scientific account of the chain reaction, in March 1934, Leo Szilard wrote to Sir Hugo Hirst, founder of the British General Electric Co. ‘As you are on holiday you might find pleasure in reading a few pages out of a book by H. G. Wells which I am sending you,’ wrote Szilard confidently to Sir Hugo, who was staying at Cannes on the French Riviera. ‘I am certain you will find the first three paragraphs of Chapter The First (The New Source of Energy, page 42) interesting and amusing…’
The pages Szilard posted to the South of France are some of the most evocative in Wells’s novel. They concern a scientist, Holsten, and his discovery of how to release the energy of the atom. Leo Szilard believed that he had actually worked out how to do this and now he wanted Sir Hugo – a potential financial backer for the essential experiments that would now have to be conducted – to share his excitement. Strangely enough, Wells’s scientist makes his discovery in 1933 while working in London’s Bloomsbury. The significance of this coincidence in time and space was not lost on Leo Szilard. ‘Of course, all this is moonshine,’ he told Sir Hugo, echoing Rutherford,
but I have reason to believe that in so far as the industrial applications of the present discoveries in physics are concerned, the forecast of the writers may prove to be more accurate than the forecast of the scientists. The physicists have conclusive arguments as to why we cannot create at present new sources of energy for industrial purposes; I am not so sure whether they do not miss the point.34
When it came to the future of atomic energy, Szilard sided with the novelists rather than the physicists.
H. G. Wells’s scientist, Holsten, was born in 1895, just three years before Leo Szilard. Like many children of his generation, Holsten’s interest in the realm of the atom was sparked by Sir William Crookes’s spinthariscope. The stellar scintillations of the disintegrating radium atom viewed through this toy opened up new worlds of possibility. Holsten was 38 when he solved ‘the problem of inducing radio-activity in the heavier elements and so tapping the internal energy of atoms’.35 The year was 1933, twenty years into the future when Wells was writing, but the very year in which Szilard grasped the significance of a neutron chain reaction.
Holsten is a Faustian scientist, ‘possessed by a savage appetite to understand’.36 Faust searched for the ‘the inmost force / That bonds the very universe’.37 Holsten discovered that secret by setting up ‘atomic disintegration in a minute particle of bismuth’. This explosive reaction, in which the scientist is slightly injured, produces radioactive gas and gold as a by-product. The quest of the alchemists is over – gold can now be created on demand. But Holsten has also discovered something far more valuable than even gold: ‘from the moment when the invisible speck of bismuth flashed into riving and rending energy, Holsten knew that he had opened a way for mankind, however narrow and dark it might still be, to worlds of limitless power’.38
Caricature of H. G. Wells from 1913.
When Holsten realizes the implications of what he has found, his mind is thrown into turmoil. Like Szilard, he goes for a walk to think things through. But the knowledge of what he can now do sets him apart from everyone he passes on the street. It makes him feel ‘inhuman’, like an outsider in his own country:
All the people about him looked fairly prosperous, fairly happy, fairly well adapted to the lives they had to lead – a week of work and a Sunday of best clothes and mild promenading – and he had launched something that would disorganise the entire fabric that held their contentments and ambitions and satisfactions together.
A startling, even shocking, thought now occurs to him. Suddenly he ‘felt like an imbecile who has presented a box of loaded revolvers to a Crêche [sic]’.39 Holsten has realized that his discovery will lead to a superweapon.
In what is one of the most powerful moments in the book, Holsten then meets an old school friend who is out walking his dog, and they stop to talk. Holsten tries hard to tell his friend ‘the wonder of the thing’ he has discovered. But the gulf in understanding between the scientist and the ordinary man in t
he street is unbridgeable.40
Before he strikes his fateful bargain with Mephistopheles, Goethe’s Faust longs for ultimate understanding of the universe and its laws. In a poignant scene, Outside the City Gate, he walks with his assistant among his fellow citizens. It is a holiday, and there is dancing and singing. Suddenly it is painfully clear to Faust that he will never be like these ordinary people. He will always be an outsider. His intense, almost physical desire for knowledge and understanding isolates him from the trials and joys of everyday life.
‘Two souls, alas, are dwelling in my breast,’ cries the tormented Faust. One part of him knows ‘joyous earthy lust’, or physical experience. But ‘the other soars impassioned from the dust’, a hauntingly beautiful expression of intellectual yearning – the desire for knowledge, for science.41 Faust, the archetypal scientist, has tasted the forbidden fruit. Now he cannot rest, but must engage in a lifelong quest for knowledge, even if the price be self-destruction and the loss of his immortal soul.
On his walk, Holsten, like Faust, passes the carefree Sunday strollers, a fallen man mingling with the innocent. In his head is the knowledge that will quite literally bring the world they know to an end. He sees himself ‘a loose wanderer from the flock returning with evil gifts from his sustained unnatural excursions amidst the darknesses and phosphorescences beneath the fair surfaces of life’.42 Holsten is Doomsday Man personified.
The moral crisis Holsten experiences is Faust’s, but it is also the dilemma facing all scientists in the modern age. As if in recognition of the universal resonance of such a moment, Glenn Seaborg, who discovered the explosive element used in the Nagasaki bomb, described how when he heard in 1939 that the uranium atom had been split, he walked ‘the streets of Berkeley for hours’, his mind alive with the beauty and the terror of the moment.43
