by P. D. Smith
After this conversation it was apparent to Leo Szilard that he and Fermi had very different attitudes to the implications of fission: ‘We both wanted to be conservative, but Fermi thought that the conservative thing was to play down the possibility that this may happen, and I thought the conservative thing was to assume that it would happen and take all the necessary precautions.’64
Szilard now began to fight two battles to save the world. The first was scientific: to prove that atomic power was finally within reach. The second was political: he wanted to prevent German scientists from discovering the secret of atomic energy first. His letter to Joliot-Curie was part of this battle. But scientists always abhor secrecy, and the French scientists failed to recognize the threat from German science. When Joliot-Curie discussed it with his colleagues, Hans von Halban’s view was that ‘we would be mad not to publish’. Lew Kowarski – a fan of H. G. Wells – agreed: ‘someone will be first; why not us?’65
They therefore rejected Szilard’s proposal and instead began working flat out to prove that a chain reaction was possible. Their groundbreaking research papers, published in March and April 1939, would, as Kowarski later put it, ‘set alarm bells ringing in the major capitals’, including Berlin.66 For the time being, Leo Szilard had to admit defeat on this front.
In his scientific battle, Szilard made better progress. Together with Walter Zinn, who later helped to build the Chicago atomic pile, he set up an experiment at Columbia University to see whether neutrons were produced when the uranium atom splits in two – if they were, then his idea of a self-sustaining chain reaction would finally have become reality. Since that day in London in 1933 when he first thought of how to release the energy of the atom, Szilard had been trying to convince other people. Just the year before, in 1938, General Electric sent Szilard packing with the insulting comment that nuclear energy was strictly ‘for the science fiction fans’.67 Now, in a deserted laboratory on a cold March evening in 1939, Szilard would finally discover whether he had been tilting at windmills for the last six years.
At first the screen of the oscilloscope remained blank. Then Walter Zinn realized that it wasn’t plugged in. Both men laughed nervously at this silly mistake and peered again at the grey screen. They didn’t have long to wait. ‘We turned the switch and we saw the flashes,’ recalled Szilard. Uranium fission did create additional neutrons. ‘We watched them for a little while and then we switched everything off and went home. That night there was very little doubt in my mind that the world was headed for grief.’68
By early summer 1939, rapid progress had been made towards achieving a chain reaction. In February, Niels Bohr had revealed that it was the isotope of uranium known as uranium-235 that was most susceptible to fission. But it existed in very small quantities, at the level of 0.7 per cent in natural uranium, which is nearly all uranium-238. Anyone wanting to produce a bomb would first have to overcome the huge practical problem of separating uranium-235 from natural uranium. As far as Bohr was concerned, this meant that no one would be building atomic bombs in the near future.
In March, both Szilard and Joliot-Curie detected secondary neutrons during the fission of uranium. The following month, Joliot-Curie and his team published their view that a chain reaction using uranium was within reach. In Germany, the physical chemist Paul Harteck – a friend of Szilard’s who had once worked at Fritz Haber’s institute in Berlin – promptly contacted the War Office. ‘We take the liberty of calling your attention to the newest development in nuclear physics,’ Harteck wrote, ‘which in our opinion, will probably make it possible to produce an explosive many orders of magnitude more powerful than conventional ones… That country which first makes use of it has an unsurpassable advantage over the others.’69
In America, while the German War Office was considering Harteck’s research proposal for a super-explosive, the New York Times reported that members of the American Physical Society had argued publicly ‘over the probability of some scientist blowing up a sizeable portion of the earth with a tiny bit of uranium’. The physicists argued that if the difficulties surrounding the separation of uranium-235 could be surmounted, then the ‘creation of a nuclear explosion which would wreck as large an area as New York City would be comparatively easy. A single neutron particle, striking the nucleus of a uranium atom… would be sufficient to set off a chain reaction of millions of other atoms.’70
Even before this dramatic claim was made, Eugene Wigner had written to Leo Szilard telling him that he now felt ‘very strongly, that the US Government should be advised of the situation’.71 Szilard agreed. In July, three members of the Hungarian Quartet met in New York to decide on a plan of action. Wigner travelled to the metropolis from Princeton. Edward Teller was teaching during the summer at Columbia University. Leo Szilard was busy designing what became in 1942 the world’s first operational nuclear reactor.
All three (together with another colleague from Berlin, Victor Weisskopf) had been involved in the attempt to suppress news of advances in fission research. Now that the details were out in the open, they agreed that the situation was serious. The publication the previous month of Siegfried Flügge’s paper ‘Can Nuclear Energy Be Utilized for Practical Purposes?’ had shocked them all. Flügge was a colleague of Otto Hahn’s at the Kaiser Wilhelm Istitute for Chemistry. It was obvious that German scientists were hot on the trail of the atomic bomb. In England, Joseph Rotblat came to the same conclusion, and his thoughts turned to designing an atomic bomb, despite his hatred of war.
The Hungarians had already made initial approaches to the US military, but without success. ‘It’s just some crazy worrying by a few foreigners,’ said Wigner, summing up the attitude of the American authorities.72 What also concerned the Hungarians was the possibility that the Nazis might gain control of the rich uranium mines in the Congo, then a colony of Belgium. In an attempt to prevent this, Szilard and Wigner decided to enlist the help of the most famous scientist on the planet, Albert Einstein, who just happened to be close friends with the Queen of Belgium.
The BBC correspondent Alistair Cooke once marvelled that ‘Szilard – a scientific brain beyond our comprehension – couldn’t drive a car’. His driver on Wednesday 12 July was Wigner, who collected Szilard from his hotel in his Dodge coupé. Together they drove out to Peconic, Long Island, where the great physicist was on vacation, dividing his time between his two great passions – physics and sailing.
According to Wigner, they found the 60-year-old Einstein ‘dressed in an old shirt and unpressed pants, apparently perfectly content to be thinking only of physics’.73 They sat together on the porch of the white weatherboarded cottage, drinking iced tea and discussing the latest application of physics – atomic bombs. Einstein was still ploughing his lonely furrow in physics, searching for the elusive theory that would unify the quantum with the cosmic realm. He had not heard about fission. But when he realized that chain reactions might be possible, he said softly, ‘Daran habe ich gar nicht gedacht’ – ‘I hadn’t thought of that.’74
Einstein was ‘horrified’ by the idea that the Nazis might build an atomic bomb.75 With that in mind he was happy to sound the alarm, even though, as Szilard said later, ‘it was quite possible that the alarm might prove to be a false alarm.’76 Sitting on his Peconic porch, Einstein dictated a letter in German for the Belgian ambassador in Washington, warning that superbombs might be made using uranium from their mines in the Congo. It was also agreed to send a letter to the State Department informing them that they intended to warn Belgium. After this, the two Hungarian scientists returned to New York. Before they left, they watched as Einstein climbed into his dinghy and sailed off contentedly across the bay.
‘This story shows that we were all green,’ Szilard said later. ‘We did not know our way around in America, we did not know how to do business, and we certainly did not know how to deal with the government.’77 Instead of posting the letters, Szilard turned to some insiders for advice. One of the men he talked to was Dr A
lexander Sachs, the vice president of a Wall Street bank and a personal friend of President Roosevelt. Sachs told Szilard that they had it all wrong. This was a matter for Roosevelt himself.
Albert Einstein and Leo Szilard re-enact the writing of their letter to President Roosevelt, for the 1946 ‘March of Time’ documentary Atomic Power.
So Szilard made another journey out to Peconic to see Einstein, this time chauffeured by Edward Teller. Einstein greeted them in his dressing gown and slippers and dictated a new letter. But it was no simple matter writing to the President of the United States of America. ‘We did not know just how many words one could put in a letter which a President is supposed to read. How many pages does the fission of uranium rate?’78 Einstein suggested a brief outline of a letter, and Szilard returned to New York in Teller’s 1935 Plymouth to prepare two versions for Einstein’s approval. The typist hired by Szilard soon decided that he was a ‘nut’ when she heard that the letters were addressed to Roosevelt and concerned a new superbomb.79
In the end, Einstein preferred the longer of the two versions. This letter, dated 2 August 1939, is the one that Sachs eventually took to his friend, President Roosevelt. At auction in 1986, the shorter version (which was not even sent) sold for $220,000. Just as Jacobus Laningdale went to the President with his idea for a biological weapon in Jack London’s story, so now the physicists presented their proposal for a superweapon to FDR himself. Einstein and Szilard’s letter warned him that ‘extremely powerful bombs’ could be made using uranium. ‘A single bomb of this type, carried by boat and exploded in a port, might very well destroy the whole port together with some of the surrounding territory,’ they wrote. They warned the President that the Germans were already trying to build the bomb, employing the formidable scientific resources at Dahlem in Berlin where both Einstein and Szilard had once worked.
As well as drawing the President’s attention to this dangerous situation, the letter also proposed that scientists should begin working closely with the government:
In view of this situation you may think it desirable to have some permanent contact maintained between the Administration and the group of physicists working on chain reactions in America. One possible way of achieving this might be for you to entrust with this task a person who has your confidence and who could perhaps serve in an inofficial [sic] capacity.80
It is clear that Leo Szilard saw himself as ideally suited to fulfilling this role. But although over the last six years he had spent more time than anyone else thinking about the chain reaction and its impact on society, this project would prove too big even for the ‘Director General’.
14
Conceived in Fear
Black as vermin, crawling in echelon
Beneath the cloud-floor, the bombers come:
The heavy angels, carrying harm in
Their wombs that ache to be rid of death.
This is the seed that grows for ruin,
The iron-embryo conceived in fear.
Cecil Day-Lewis, ‘Bombers’ (1938)
In the aftermath of World War I, Pierrepont B. Noyes, an American Rhineland Commissioner, wrote a thriller called The Pallid Giant about the causes of war. Noyes identified fear – the ‘pallid giant’ of the title – as the culprit. ‘The ghastly development of war’s destructiveness during the last fifty years’, he wrote, has made nations ‘think in terms of fear, and there is no more deadly poison in human counsels than fear.’1
The Pallid Giant was reissued after the destruction of Hiroshima and Nagasaki. The novel described how a previous, advanced civilization had wiped itself off the face of the earth in a ‘holocaust of self-destruction’.2 In 1909, Frederick Soddy had speculated about a mythical Eden, an ancient civilization created and destroyed by the power of the atom. Now, in the atomic age, this idea gained a new significance. ‘Think for a moment,’ says a character in The Pallid Giant,
what could happen to a race of men whose material inventions placed in their hands unlimited power for destruction before they had developed moral inhibitions sufficient to prevent their using that power to destroy themselves… Put it another way: what would happen to men possessed of a 100 percent power to conquer others and only 25 percent power to conquer themselves?3
For many people in 1945, this seemed an accurate assessment of the situation facing the world.
Noyes suggests that when a civilization discovers the greatest secret of nature, atomic energy, it marks the final stage in the evolution of human destructiveness. Then, as happens in The Pallid Giant, the way is clear to create ‘a force of universal death’, the ultimate superweapon. For Noyes in 1927, this was a scientific weapon about which there had been much speculation – an atomic death ray.4 After the invention of this weapon there could be no talk about a war to end wars, as Wells had suggested in The World Set Free. According to Noyes, in a world where armies face each other with weapons of absolute destructiveness ‘war would end all war, by ending man’.5
Noyes was right. It was fear that led to the invention of the atomic bomb. The émigré scientists who had already suffered at the hands of the Nazis were understandably afraid of what Hitler would do if armed with an atomic bomb. But paradoxically, these scientists were also motivated by the hope that – as H. G. Wells had imagined back in 1913 – atomic energy would herald a new dawn for human civilization. The superweapon itself would, if terrible enough, force the world to renounce war. But the utopian Wells was also enough of a realist to know that much blood would be shed first. Utopia would only be achieved after humankind had passed through the elemental fires of the atomic bombs. For many physicists, including Leo Szilard, Eugene Wigner and Edward Teller, even after the horrors of Hiroshima and Nagasaki, still the dream lived on – the dream of unlimited energy and absolute power.
Fear made the atomic bomb a reality in 1945. Fear of Hitler’s scientists galvanized America’s unequalled military, industrial and – thanks to the Third Reich’s anti-Semitic policies – scientific resources into making a supreme effort. As it turned out, this fear, although not irrational, was unfounded. The German atomic bomb project, riven from the start by internal rivalry, never came near to creating a usable weapon. Despite possessing some of the world’s greatest scientists – albeit Aryan ones, such as Hahn and Heisenberg – their science was flawed from the outset. For instance, they remained unaware that pure graphite could be used in a reactor (something Szilard grasped at the start of the war) and were convinced that the critical mass needed for a bomb was measured in tons rather than a few pounds.
In its scale and speed, the Manhattan Project was an accomplishment beyond even the imaginings of most science fiction writers. William Laurence, the New York Times reporter who was the only journalist allowed access to the atomic bomb project during wartime, recalls chemist and Harvard president James B. Conant saying to him, ‘they won’t believe you when the time comes that this can be told. It is more fantastic than Jules Verne.’ The pragmatic journalist replied bluntly: ‘They’ll believe it if it works!’6
By 1947, Laurence could boast that ‘only three other men have seen as many of the bombs in action as I have’. Like many others, he was clearly awestruck by the terrible power of the superbomb. Standing in front of the Fat Man plutonium bomb before it was dropped on Nagasaki, Laurence felt that he was ‘in the presence of the supernatural’.7
According to Laurence, one of the Manhattan Project’s greatest achievements was ‘bringing together into a smoothly functioning team the long-hairs and the short-hairs, who in normal peacetime used to growl at each other from a safe distance’.8 It was not the first time that scientists had mobilized on behalf of their nation in wartime: Chemists in America and Europe had done so during World War I. But the scale of the Manhattan Project dwarfed all previous scientific collaborations with the military. Its success made it a model for weapons research in the cold war. The long-hairs and short-hairs were stuck with each other.
Leo Szilard once said that his favourite pa
st-time was ‘baiting brass hats’.9 He was never happy taking orders from the military, or anyone else for that matter. Einstein’s letter to President Roosevelt – partly drafted by Szilard – showed the key role the Hungarian physicist thought he himself should play in the development of the atomic bomb. Britain and Germany were already at war when Alexander Sachs finally saw Roosevelt in October 1939. The President didn’t understand the physics, but he immediately grasped the potential significance of a new super-explosive and wasted no time in setting up a committee to investigate Szilard’s claims.
The Advisory Committee on Uranium met for the first time on 21 October 1939. Wigner, Teller, Szilard and Sachs were present, along with Lyman J. Briggs, Director of the Bureau of Standards, America’s national physics laboratory since 1901, as well as Lieutenant Colonel Keith F. Adamson and Commander Gilbert C. Hoover, ordnance experts from the army and navy respectively.
At the meeting, Szilard patiently explained his idea for a uranium– graphite pile and the possibility that one uranium bomb could have the power of 20,000 tons of chemical explosive. Colonel Adamson, from the Aberdeen Weapons Proving Ground, was distinctly unimpressed by this talk of an atomic bomb that could devastate an entire city. He told Szilard that he had been standing next to an ordnance depot when it exploded and the force had not even knocked him down. The colonel openly sneered at the science fiction idea of a superweapon. ‘At Aberdeen,’ he told the scientists, ‘we’re offering a $10,000 reward to anyone who can use a death ray to kill the goat we have tethered to a post. That goat is still perfectly healthy.’10
