by P. D. Smith
In the same year as Einstein’s seminar on statistical mechanics, another person who would play a key role in the history of the atomic bomb was also in Germany. During the summer of 1921, Robert Oppenheimer, then aged 17, visited the country his father had left in 1898. His grandfather, who lived in Hanau, had given him a collection of minerals. To add to it, Robert visited the St Joachimsthal mine, the source of Marie Curie’s uranium ore and of the uranium eventually used in the atomic bomb. It was this trip that sparked his lifelong passion for science.
True to his impatient nature, Leo Szilard started his doctorate ‘rather early’ in his studies at the University.41 Max von Laue had suggested to him a problem on the theory of relativity, and Szilard spent the end of 1921 grappling with the theory’s subtleties. Von Laue had been one of the first physicists to appreciate the revolutionary nature of Einstein’s thinking. In the year that Einstein first wrote down the equation E = mc2, von Laue had visited the 28-year-old patent officer in Berne and together they spent a day walking round the city’s medieval streets. As the two men journeyed to the frontiers of physics and back again, they paused on the high bridge over the River Aare, and von Laue surreptitiously dropped the cheap cigar Einstein had given him into the swirling alpine waters below. Einstein’s taste in cigars was appalling, decided von Laue, but his judgement in science was impeccable.
After six months of sustained thought, Szilard decided he couldn’t ‘make any headway’ with the problem on relativity. According to Wigner, Einstein’s seminars on statistical mechanics gave Szilard ‘sour feelings toward higher mathematics’. He began to suspect (wrongly, in Wigner’s view) that ‘he was not bright enough to change theoretical physics’.42 In typically combative style, he made an asset of a weakness. ‘There is no need to study mathematics,’ Szilard would say. ‘One can always ask a mathematician!’43 Einstein had the same attitude, and while working on his general theory of relativity, he did just that – he asked a mathematician, his old friend Marcel Grossmann, for help.
By Christmas 1921, Szilard knew that relativity was not going to provide him with the basis for an original thesis. He needed a new idea, and settled down to some serious thinking. ‘Christmastime is not a time to work,’ he decided, ‘it is a time to loaf, so I thought I would just think whatever comes to my mind.’44 He turned up the collar of his overcoat against the bitter winter winds and paced Berlin’s streets, deep in thought:
I went for long walks and I saw something in the middle of the walk; when I came home I wrote it down; next morning I woke up with a new idea and I went for another walk; this crystallized in my mind and in the evening I wrote it down. There was an onrush of ideas, all more or less connected, which just kept on going until I had the whole theory fully developed. It was a very creative period, in a sense the most creative period in my life, where there was a sustained production of ideas. Within three weeks I had produced a manuscript of something which was really quite original.45
Szilard had his thesis. But as he had dropped Max von Laue’s topic, he didn’t dare take it to him. Instead, he turned to the world’s most famous physicist. At the end of one of Einstein’s seminars, Szilard asked him if he would listen to his idea.
‘Well, what have you been doing?’ asked Einstein.
Szilard told him about the idea that had come to him while walking through the icy streets of Berlin. When he had finished, Einstein was astonished.
‘That’s impossible. This is something that cannot be done!’
‘Well, yes, but I did it,’ replied Szilard.
Einstein looked incredulous. ‘How did you do it?’46
For the next ten minutes Szilard explained, and at the end Einstein smiled. Not for the last time in his life, Leo Szilard had done the impossible.
His thesis was on the second law of thermodynamics. He had made good use of Einstein’s seminars, for he drew on statistical mechanics rather than experimental evidence to demonstrate the validity of this fundamental principle of physics. With uncharacteristic modesty, Szilard described it as ‘not really a beginning, it was not the cornerstone of a new theory, it was rather the proof of an old theory’.47 Reassured by Einstein’s reaction, Szilard plucked up the courage to visit Max von Laue. The following morning he received a telephone call from von Laue accepting the thesis.
Six months later, Szilard extended his thinking on thermodynamics and wrote a paper which explored the ‘relationship between information and entropy’. In the 1950s, at the start of the computer age, this paper was hailed as ‘a cornerstone of modern information theory’.48
There was no doubting the originality of Szilard’s insights into these problems. But Einstein was clearly concerned that his young friend’s personality might make it difficult for him to settle into academic life. After all, Einstein’s informal manner and approachability was the exception not the rule in German academia. Once Leo Szilard was awarded his PhD, Einstein suggested that he consider following in his own footsteps, and apply to work in a patent office. ‘They were the happiest years of my life,’ said Einstein. ‘Nobody expected me to lay golden eggs.’49
Einstein was a shrewd judge of character: he could see that Leo Szilard was a maverick. This would be both Szilard’s great strength and his weakness. It allowed him to think outside the box and see atomic bombs where others saw only disintegrating atoms. The downside was that because his ideas were so far ahead of current thinking, less perceptive scientists were often exasperated by what they saw as his flights of fancy. In his article on future war, Hugo Gernsback had said ‘modern science knows not the word Impossible’.50 That could have been Leo Szilard’s motto.
9
The Inventor of All Things
Our conscience is clear… and that is the essential thing. Our intentions were pure. Our ideal was to create.
Pierre Boulle, ‘E = mc2’ (1965)
Albert Einstein was once asked where his laboratory was. He grinned like a schoolboy and held up his pen. Leo Szilard was also – as Eugene Rabinowitch said – ‘an idea man par excellence’.1 Experimentalists such as Enrico Fermi were often annoyed by Szilard’s reluctance to get his hands dirty in the laboratory. Szilard didn’t help matters by appearing unexpectedly in laboratories and offering unasked-for advice to other scientists about how best to conduct their experiments. The physicist Isidor Rabi once pleaded with Szilard to leave him in peace. ‘You are reinventing the field. You have too many ideas. Please, go away!’2 However, Szilard’s advice often turned out to be right. This habit earned him the nickname ‘Director General’ at the Kaiser Wilhelm Institute where Eugene Wigner worked in the mid-1920s. Leo Szilard could be a difficult, even infuriating character, but those who saw beyond this came to value his insights.
Another Hungarian friend of Szilard’s in Berlin, Dennis Gabor, remembered that he
hardly ever went to the lab – he sat out in the garden in a deck chair and thought. His chief activity was talking to friends: he rang them up, he talked with them in cafés. He knew everyone and gladly gave advice to all physicists and biologists. Szilard wanted to discuss everything, and to pass on his ideas by word rather than by writing.3
According to Gabor, ‘he used to discuss all his inventions with me. I was so full of admiration that I felt quite stupid in his presence. Of all the many great men I have met in my life, he was by far the most brilliant.’4 Gabor recalls a conversation in a Berlin cafe – probably Szilard’s favourite, the Romanisches Café – during which Szilard explained how to design an electron microscope. In 1931 he even patented this idea, but the Nobel prize for inventing an electron microscope went to another scientist, Ernst Ruska, in 1986.
Leo Szilard also patented a design for a particle accelerator, in 1929 – several years before Ernest O. Lawrence, who received a Nobel in 1939 for his cyclotron. Szilard was always ahead of the game, whether it was physics or food: in the 1950s the now portly physicist even invented a means of producing low-fat cheeses for epicures worried about their waistlin
es. ‘Had he pushed through to success all his new inventions,’ said Dennis Gabor, ‘we would now talk of him as the Edison of the twentieth century.’5
Szilard often played the role of catalyst, inspiring others with his original ideas. ‘He loves to seize a problem in its early, exciting stage, and to work on it furiously until he begins to glimpse the answer,’ said journalist Alice Kimball Smith. ‘Then he is likely to move on to something else, leaving the tedious labor – and the laurels – to others.’6 His friend, editor and peace campaigner Norman Cousins, considered him to be one of the most significant scientists of his generation: ‘The restless inventiveness of his mind knows few modern counterparts.’7 A colleague in the 1950s described Szilard simply as ‘the inventor of all things’.8
Eugene Wigner shared this respect for Szilard’s achievements: ‘Throughout my long life I had the chance to meet very talented people, but I never met anybody more imaginative than Leo Szilard. No one had more independence of thought and opinion.’ After a moment’s reflection, he added: ‘You may value this statement better if you recall that I knew Albert Einstein as well.’9
It was Szilard, after all, who realized that in the early 1930s atomic energy was within reach. He was at least seven years ahead of Einstein in this area. It would be the maverick Hungarian scientist who eventually broke the news to the great physicist in 1939 that the uranium atom had been split. From boyhood, Szilard had enjoyed reading H. G. Wells and futuristic fiction. After the atomic bombs were dropped on Japan, he even began writing Wellsian stories himself to express his fears for the future. By contrast, Einstein had no time for science fiction, preferring detective fiction. Scientific fiction seemed to give Leo Szilard the creative edge over his mentor and indeed other scientists, such as Rutherford and Fermi, who in the 1930s would dismiss his ideas for releasing atomic energy. Science fiction allowed him to glimpse the future.
Eugene Wigner was Szilard’s most loyal friend, and their friendship would last a lifetime. Wigner recalled that when they first met, at the Berlin physics colloquia in 1921, his ‘first impression was of a vivid man about 5 feet 6 inches tall, a bit shorter even than I was. His face was a good, broad Hungarian face. His eyes were brown. His hair, like my own, was brown, poorly combed, and already receding from his forehead.’ He added, drily, ‘A full head of hair is quite nice, but we survive without it.’ Szilard spoke fluent German, ‘with a striking clarity and vigor’. Like some unpredictable quantum phenomenon, he also had the unnerving ability to appear and disappear when you least expected it: ‘You might see him for a moment at the colloquium, but then he was gone. Several days later, he appeared at your front door with several bold ideas and not quite enough patience. Leo Szilard was always in a hurry.’10
According to Wigner, Szilard realized during Einstein’s seminars that he would not be able to make a significant contribution to quantum mechanics. ‘Complex abstractions rarely appealed much to Szilard.’11 Instead, from 1922, despite Wigner’s efforts to draw him into his own research into quantum mechanics, Leo Szilard struck off in a new direction, collaborating with Herman Mark in his research on X-rays at Dahlem.
In the space of two years, Leo Szilard had established a reputation for himself in one of the foremost physics research institutes in the world. The hopeful student of electrical engineering who stepped off the train from Vienna in January 1920 had come a long way in a very short time. His brother Bela recalls how in those first months ‘Leo spent most of his time just sitting and thinking, seldom reading course books, and rarely attempting the practical exercises’. His logical attitude to life sometimes bemused his brother. One evening Bela said, ‘Close the window; it’s cold outside.’ Leo replied: ‘I will close the window, but that will not make it less cold outside.’12
In their spare time, the two students of electrical engineering amused themselves by dreaming up fantastic, Heath-Robinson solutions to imaginary problems. One idea was to speed up haircuts by applying a slight electric current to barbers’ chairs, so that customers’ hair would stand on end. Another was prompted by the sight of Berlin women repeatedly pulling up their stockings: Leo proposed to prevent slippage by equipping stocking tops with flexible iron threads and placing magnets in women’s jacket pockets.13 Such scientific flights of fancy had amused the brothers since childhood.
Eugene Wigner described Szilard as a child prodigy, like their mutual friend and mathematical genius John von Neumann.14 Leo Szilard himself recalls that he was ‘a very sensitive child and somewhat high-strung’.15 Like Einstein, Szilard had a family background in engineering. His father was a civil engineer and his uncle was an architect who designed the family home, a lavish villa still standing at 33 Fasor, Budapest. This became home to three generations of his mother’s family, and Szilard grew up in a house which echoed to the games and songs of seven children. His cousins and siblings soon recognized that Szilard was ‘the brainiest among us’. His liking for logic also showed up early. His cousins, the Scheibers, decided he was ‘number headed’.16
As a child, Szilard was a keen reader. Like many other boys of his generation he loved the adventure stories of the best-selling German writer Karl May. Encouraged by his father’s own tales of his work as an engineer, from an early age he also read books about engineers, such as Van Eyck’s accounts of the history of engineering. Throughout the first half of the twentieth century, engineers were portrayed as dynamic heroes in German popular fiction. An example is Bernhard Kellermann’s futuristic Der Tunnel (1913), about an engineer’s epic struggle to build the first transatlantic tunnel. After World War I, the Zukunftsroman, or future novel, became an immensely popular genre in Germany. The technological adventures of Hans Dominik were spectacularly successful, selling in their millions. The Faustian exploits of the engineers now turned towards the final frontier – the conquest of space. In the late 1920s, the dream of interplanetary travel would also inspire Leo Szilard.
Thanks to Szilard’s childhood idolizing of heroic engineers, he became an avid reader of Der gute Kamerad (‘The Good Friend’), a monthly boys’ magazine. It was a German version of Hugo Gernsback’s The Electrical Experimenter, a mixture of scientific romances and articles about how to build electrical gadgets. Szilard himself was never much good with his hands, so Bela was put in charge of the practical construction work. They loved building things, and the brothers were over the moon when an uncle returned from a trip to England with a Meccano set. Again, it was Bela who did the construction and Leo who supplied the designs. Typically, his ideas were impossibly bold for the meagre number of Meccano parts in their set. But as a child and an adult, Leo never let his dreams be limited by practicalities.
For the young Leo Szilard, the stories and engineering projects in Der gute Kamarad provided a springboard into the magical world of the imagination. It was a world he never quite left behind. His unique creativity remained deeply rooted in this culture of technological invention. During his formative years, popular adventure fiction in Europe and America idealized the figure of the lone inventor, a character familiar from the pages of Jules Verne and H. G. Wells. In 1915, Hugo Gernsback, whose pulp magazine Amazing Stories would soon herald a new scientific genre of fiction, pointed to people like Edison, Bell and Marconi as the heroes of the modern age: ‘Always it is a dreamy pioneer, an intrepid free-lance, aflame with enthusiasm, who enriches his country with a radically new labor-saving device or way of utilizing energy.’17 In superweapon fiction, such as The Man Who Rocked the Earth, the scientist is typically a solitary genius, rational, honest and ‘aflame with enthusiasm’ for his latest ideas. His only flaw is arrogance, a permissible trait in one so obviously brilliant and destined to save the world. Leo Szilard, the ‘lonely pioneer’, fitted this description perfectly.18
At a time when electricity was replacing gas lighting in the more affluent homes of Budapest, the young Szilard’s imagination was gripped by the new invisible power source. As a boy, Einstein had been
‘The War of the Fut
ure’: a 1928 cover illustration for the children’s magazine Le Petit Inventeur (No. 23). Let us hope, says the caption, that neither we nor our descendants will ever have to experience those terrible wars in which the sciences are applied in the dreadful cause of destruction.
similarly intrigued. His father and uncle ran an electrical engineering business in Munich. Born in 1879, the year in which the electric light bulb was invented, Einstein grew up listening to his uncle’s excited descriptions of his latest electrical invention. This experience was a major influence on his future scientific interests.
Szilard soon progressed from Der gute Kamarad to Gyözö Zemplén’s Theory and Practical Applications of Electricity, quickly absorbing the dry textbook’s explanations and experiments. Szilard, the budding director general, supervised his brother’s construction of a two-way crystal radio telegraph. Their grand idea was to send messages from one end of the family’s large apartment to the other. But because Szilard could not be bothered to learn Morse code, the project failed. Their next electrical endeavour was potentially more dangerous. The brothers placed electrodes in a glass jar of water and watched as hydrogen and oxygen bubbled up. But as they couldn’t work out how to capture the gases separately, they soon lost interest. ‘That’s just as well,’ Bela told his brother’s biographer, ‘because Leo’s next step was to explode the gases with a match to enjoy a “big bang”.’19
