During 1938, Strauss and Szilard did manage to collaborate on research to investigate how radiation might eliminate budworms from high-quality cigar tobacco.32 Their efforts to irradiate pork did not go as well. Without warning the public, meat packers feared the spread of trichinosis in 1938, and that summer, with Strauss’s backing, the Szilard brothers conducted research to determine if X-ray doses were effective for treating pork: Leo, at the Strong Memorial Hospital in Rochester; Bela, at the Royal Victoria Hospital in Montreal. Leo also irradiated Canadian bacon, frankfurters, and salami at Columbia University and left them for months in the Liebowitz family’s refrigerator, checking now and then to test their appearance and taste.33 Leo and Bela met in Chicago with the National Live Stock and Meat Board to recommend an ambitious research program but scared them with an impromptu cost estimate for irradiation of $200 per hog carcass.34
Szilard’s flighty independence eventually lost him his last reliable income, the part-time appointment at Oxford, while also straining his English friendships. Although the university’s board of faculty knew that Szilard would be in America for several months a year to monitor nuclear research, it also expected him to lecture eight times a term for two of each year’s three terms—ironically, the subject proposed, “High Tension Physics and Nuclear Stability,” described Szilard’s personal life and work aptly.35
In New York that summer, Szilard chanced to meet Fermi’s colleague, Emilio Segrè. “Oh, what are you doing here?” asked Szilard in their surprise encounter.
“I’m going to Berkeley to look at the short-lived isotopes of element 43 [Technetium],” said Segrè. “I’ll work there the summer, and then I’ll go back to Palermo.”
“You are not going back to Palermo?” asked Szilard. “By this fall, God knows what will happen! You can’t go back.”
“Well,” Segrè replied, “I have a return ticket. Let’s hope for the best.”
36 As usual, Szilard was expecting the worst. “I find to my amazement that the so-much feared summer heat of New York is quite comfortable to me,” he wrote to Francis Simon. “Or do you think that the influence of my present political sympathies upon my attitude toward the heat could go so far as to let that heat appear to me as enjoyable [?].”37
When Maurice Goldhaber landed in New York, Szilard showed him around the city and brainstormed about continuing a collaboration they had begun in England. Goldhaber was off to become an assistant professor of physics at the University of Illinois. Szilard was clearly ambivalent about returning to Oxford because of his fears about the coming war, yet when Lindemann forced him to accept the lectureship’s terms, he agreed.38 Probably as frightening to Szilard as the coming war was the reality of a fulltime job. To Szilard’s friends, his uncertainties about returning to Oxford became annoying. As Francis Simon wrote:
There is no gainsaying the fact that you do not make it easy for the people here to do something for you. One hardly hears anything from you, and if one does, then there are only a few lines which do not tell anything of importance, and nobody knows when you actually intend to come back. Then one hears suddenly from a visitor who has seen you on the other side that you have been engaged in psychology for some time—because that is much more important than neutrons. Of course, that doesn’t spur on people, either, to make great efforts on your behalf. Now you write that this lectureship thing is not convenient for you if you have to lecture for two terms. . . .
Once again I have to talk to you in all seriousness. All those to whom I have spoken are angry with you, whether this is [his AAC colleague] Miss [Esther] Simpson or [his former Oxford landlord James] Tuck or anybody else; and these are the people who wish you well! You do not get anywhere with your erratic actions, with your suddenly being unaccounted for; and it would be a pity if this would lead to failure. If you continue to act in that way, you cannot expect ever to get sensible employment, and one cannot help to say that one couldn’t blame anybody but you for this. At one time an American told me that there are quite a few people who are dying to converse with you for a few days but none who would like to offer you a job. I feel that this is, alas, quite correct.
Of course, you could say that you prefer to continue your lifestyle as before and not to give consideration to others and to their customs and habits. However, in that case, you have to accept the consequences and not ask such others for favors.
I don’t say these things to you to annoy you, but I feel it is necessary, and many others feel the same way, but apparently nobody is telling you so. Perhaps it would be best that you marry, and preferably a woman who considers the realities somewhat more than you do. Of course, the responsibility for giving such advice is heavy, but you will not follow it anyway. . . . With heartfelt greetings, from my wife, too.39
Szilard’s reply showed little regret:
Many thanks for your admonitions. I fear you are right.
The remedy [marriage], however which you suggest, appears to be somewhat too drastic. Anyway, why should a woman who has sense of reality mary [sic] a man who has none. Combinations the other way around seem to be much more common and appropriate.
Yours, Leo Szilard40
This insouciance masked Szilard’s darker political fears, which were aroused in late August. He had journeyed to Champaign, Illinois, to finish experiments begun with Goldhaber in England, and while there he sat in the living room of his apartment near campus, listening on his radio to news of the advancing Munich crisis.41 Both now refugees, Goldhaber and Szilard met in Champaign with physicist R. D. Hill and together checked the calculations they had made months earlier when bombarding indium with fast neutrons at Oxford and Cambridge. The article about their work, which they sent to the Physical Review in October 1938, is curious for its mention of “chain reactions produced in cadmium by fast neutrons,” a reference to a chemical, not Szilard’s hoped-for nuclear, process.42
Into September, Goldhaber and Szilard hunched over the radio each night to learn what would happen next.43 Years later, Szilard was proud of his prediction, made in a letter to Michael Polanyi from New York in 1935, that he would return to England until “one year before the war.” Polanyi had passed the letter around at the time, and a few people chided Szilard about it when he returned to England that June. But when the Munich Pact was signed on September 30, 1938, allowing Germany to annex the Sudetenland in northern Czechoslovakia, Szilard decided to stay in America and cabled Lindemann—eleven months before the outbreak of war.44
Brainstorming with Goldhaber in Illinois had moved Szilard to try again to test his chain-reaction idea. From Champaign he went to Chicago to consult on hog-carcass irradiation, then visited the physics departments at Madison and Ann Arbor before stopping at the University of Rochester.
In June, Szilard had begun research at Rochester in a typical manner by strolling into Bausch and Lomb Hall, the main physics building, poking around, and asking directions from the janitor. To the next person Szilard met, he announced: “Some idiot is waxing your stone floors upstairs. If he doesn’t stop, somebody is going to slip and kill himself!” Sidney Barnes, the quiet thirty-six-year-old physicist who received this greeting, ran the university’s new 6-million-electron-volt cyclotron and soon learned that the flamboyant visitor with the curious accent had more than waxed floors on his mind; his fixation was indium. Szilard still considered it his candidate for producing a chain reaction and urged Barnes to run some experiments to test a “knock-on-proton reaction.” Barnes had never heard of such a reaction because Szilard had just thought it up. A blend of curiosity and duty led Barnes to agree.
They conferred about experiments in the building’s basement, with Szilard strolling nonstop around the cyclotron: a six-foot-square magnet set on two concrete pedestals connected to a wall of wires, lights, and switches. During his June visit, Szilard came in and out of Barnes’s lab unexpectedly, vanishing and appearing as he had to Hans Bethe’s amazement in London. So when Szilard reappeared in October, Barnes was hardly surprised
and welcomed his visitor.
The “knock-on” reaction Szilard was looking for involved a proton striking an indium sample, “exciting” the nucleus to give it some energy but then flying off without actually penetrating the atom. Reactions like this had been reported at the Washington meeting that spring, and Szilard knew from his own research in Oxford that neutrons would not create this process in indium. But what about protons?45 Barnes spent several weeks on the project, with Szilard appearing unpredictably, asking about results, suggesting new techniques, then strolling out the door. Barnes could never predict when Szilard would come or go, and as it turned out, during both the June and October visits he stayed at a downtown hotel and, usually at mealtime, called on his friends from Berlin, physicist Victor Weisskopf and his wife, Ellen.46
At the university, Szilard walked about constantly as he talked with Barnes and, after pacing the cyclotron room and the adjacent basement laboratories, entered the campus underground—a network of tunnels that carried steam pipes between buildings. Waving his arms, asking and answering his own questions, Szilard led Barnes from one building to another—upstairs to the ground floor, around the lobby and halls, then back into a new tunnel.
“I don’t remember him ever sitting down,” Barnes recalled years later. “If I had anything to say, I just waited until he stopped for breath, and I’d get it in. I generally didn’t say much, though. I just asked questions.” Once Szilard saw the results of their work, he insisted that Barnes alone should publish the papers. Szilard was “not interested in credit, just in getting things done,” Barnes said.
Sidney Barnes never really understood the point of Szilard’s indium experiments. But Szilard did. Indium would not give off extra neutrons whether bombarded with protons, electrons, or other neutrons. The prediction that indium would sustain a chain reaction was wrong, just as it had been for beryllium three years before. Unfortunately, one of Szilard’s Rochester predictions proved correct: A few weeks after he first arrived, a senior faculty member had slipped on the physics building’s waxed floor and cracked his skull.47
Back in New York that November, Szilard returned to the King’s Crown Hotel and “for reference purposes” applied for a Columbia University Library card. This was a time for taking stock, for cleaning up loose ends, and in a contemplative mood Szilard sat by the hour in the cavernous library, thinking and scribbling notes and letters. To physicist Niels Bohr in Copenhagen he sent Barnes’s papers on the radioactivity of indium.48
Around the campus in December 1938, Szilard had met physicist John Dunning, whose work he had cited in his own experiments at Oxford. It was an honor, then, when Dunning invited Szilard to “tell us informally about your experiments,” at a Monday afternoon nuclear physics seminar. Szilard’s severe honesty compelled him to acknowledge failure as readily as success, and this forum would allow him to describe his failed chain-reaction theory to understanding colleagues. Still, Szilard delayed accepting Dunning’s invitation until after the Christmas holidays.49 For although Szilard’s five-year “obsession” with the nuclear chain reaction had reached a disappointing end, he couldn’t quite decide how to admit it.
CHAPTER 13
Bumbling toward the Bomb
1939
The Christmas season in New York in 1938 was gloomy for Leo Szilard, who was convinced that his secret patent for a nuclear chain reaction would not work with the element indium. Five years of research, first with beryllium, then with indium, had failed and with it his hopes for a career in nuclear physics, the specialty he had once thought he could dominate by his visionary genius.
It seemed that Szilard could persuade no one to take seriously the commercial potential for the chain reaction, in part because he refused to describe in detail the natural mechanism that he envisioned—atoms hit and split by neutrons that, in turn, release more neutrons to split more and more atoms. He wanted to entice practical businessmen to buy into an alluring promise of cheap energy. But he also wanted to protect his discoveries by cloaking the whole topic in mystery. This made Szilard seem like an impractical visionary, a “character” with a hard accent and a string of improbable ideas.
In despair over these apparent failures, Szilard drew away from the few people he knew in New York, retreating to his small room at the King’s Crown Hotel just east of the Columbia University campus. Szilard spent more time in his room, rummaging among papers and calculations or simply daydreaming in his bathtub.
That fall, Szilard’s friend Trude Weiss had begun work as an extern in the pediatrics department of Bellevue Hospital in downtown Manhattan and so spent little time either in her sublet apartment or in the Columbia neighborhood. Szilard’s brother, Bela, and his family were also living nearby, in a sublet apartment in Trude’s building, but Leo visited them only every week or two for a meal and a chat. To them he seemed distracted, apparently upset by more than his finances.
Frustrated by his apparent failure, Szilard sat down in his paper-strewn hotel room on Wednesday, December 21, 1938, and wrote a short letter to the British Admiralty. In 1935, Szilard had assigned his chain-reaction patent to the Admiralty as a way to keep it secret from the Germans, whom he feared would use the device to make atomic bombs. He mentioned to the navy patent officer the “further experiments” conducted in Cambridge and Rochester, then admitted: “In view of this new work it does not seem necessary to maintain the patent. . . nor would the waiving of the secrecy of this patent serve any useful purpose. I beg therefore to suggest that the patent to [sic] withdrawn altogether. I am, Sir, Yours very truly, Leo Szilard,”1
Szilard could not know that this day would be a turning point in the history of modern science, a vindication of his hopes and fears. All he knew as he signed this letter was that he had conceived and explained an original process for releasing the binding energy that gives atoms their structure and it didn’t work. Yet that same day, at the Kaiser Wilhelm Institute for Chemistry in Berlin, Otto Hahn and Fritz Strassmann bombarded uranium with neutrons, and it broke into two parts, or “fissioned,” And in the process it released extra neutrons. Szilard, it turned out, had been right about the chain-reaction process all along. He had just tested the wrong elements for his demonstration.
Although Szilard would not learn about uranium fission for another month, once he did, the despair of that bleak December turned to exhilaration. Then to new fear. The coming year would bring a frenzy of scientific and political activity. Indeed, during 1939, Szilard would almost single-handedly lead the physics community and the US government to join forces in atomic energy research.
Two days into the New Year the SS Franconia eased into New York harbor with Enrico Fermi and his family aboard; life in Fascist Italy had finally become too dangerous for Fermi’s Jewish wife, Laura. Fermi had left Rome a month earlier, received the Nobel Prize for physics in Stockholm, and there announced that he would accept a six-month teaching appointment at Columbia. Szilard had corresponded with Fermi since 1936, trying to interest him in experiments and control schemes for their nuclear patents, so the two physicists had much to talk about when they met, by accident, in the lobby of the King’s Crown—the Fermis had checked into the hotel while apartment hunting.
Because of his recent international fame and his appointment as a university professor, Fermi arrived at Columbia a scientific celebrity. Fermi’s Nobel Prize had been awarded for the research he conducted in Rome: bombarding different heavy atoms with neutrons and then identifying the new radioactive elements that were created. Although he had not realized it, Fermi had actually split uranium atoms with neutrons as early as 1934, the same year that Szilard had patented the chain-reaction concept. In 1938, Fermi had chosen Columbia from among six American universities, so his fateful meeting with Szilard that January brought together the two scientists in the world best able to advance the research that would produce nuclear power and nuclear bombs.
By contrast, Szilard was not well known, even to other physicists. He had worked to keep his pi
oneering nuclear research secret, and to Columbia’s physicists, including Fermi, Szilard was just an unemployed visitor who poked around the department. There Szilard would appear unannounced in the laboratories, ask questions, make suggestions, then disappear. Frequently, he called on physicist Isidor I. Rabi, whom Szilard had first met in Berlin. Szilard and Rabi sensed an affinity, perhaps from their common Austro-Hungarian heritage, and the two tried to be friendly despite widely different professional interests. On each visit Szilard suggested new experiments for Rabi and his colleagues to perform, but after several weeks of this prodding, Rabi finally became impatient. “Please go away,” he begged Szilard one day. “You are reinventing the field. You have too many ideas. Please, go away.”2
But Szilard persisted, eventually imposing his concerns on not only Fermi and the Columbia physicists but also the president of the United States. What began as Szilard’s personal crusade to harness the nuclear chain reaction would eventually become the federal government’s $2 billion program to make atomic bombs: the Manhattan Project.
At first, Fermi and Szilard rarely met during working hours—Fermi’s office was on the top floor of the new Michael Pupin Laboratory Building; Szilard worked in the basement or from his hotel room. To collaborate with Fermi, Szilard had to enlist the help of established faculty members, including Rabi and George B. Pegram, who was the physics department’s chairman and dean of Columbia College.
Szilard needed to force a place for himself at Columbia because, as he tried to explain on January 13 in a long and uncertain letter to his mentor at Oxford, returning to England seemed doubtful.
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