Szilard advised that “it may be a question of national importance to secure an adequate supply of uranium.” He referred to ore deposits in the United States, Canada, Czechoslovakia, and Russia but stressed that “the most important source” is the Belgian Congo. He suggested as a subterfuge arranging “a token reparation payment” to obtain a “large stock” of pitchblende from Belgium or the Congo, in this way concealing that “the uranium content of the ore is the point of interest.”
Large-scale experiments are necessary to test the chain reaction, Szilard said. For these he urged strengthening existing research organizations or creating new ones. Another approach he suggested might be “the collaboration of the chemical or the electrical industry. . . .” So far, Szilard reported, extra neutrons—the precursor to chain reactions—have been created with slow neutrons. Whether fast neutrons would also work was not then clear. But “if fast neutrons could be used, it would be easy to construct extremely dangerous bombs” whose “destructive power” might “go far beyond all military conceptions.” Szilard concluded that if chain reactions work, self-censorship by scientists would be advisable.37
When his technical memorandum was finished on August 15, Szilard delivered it and the longer Einstein letter to Sachs, along with a detailed letter of his own. In this letter, Szilard hinted broadly that he might be the man of “courage and imagination” who could “act with some measure of authority in this matter” between scientists and the government. Szilard reviewed his own actions since he learned about uranium fission in January and reminded Sachs that the Association for Scientific Collaboration offered a legal entity for research.
Sachs telephoned the White House for a private appointment with Roosevelt, but before it could be set up, German troops stormed into Poland at dawn on September 1, and the war Szilard had feared for years began. Immediately, Roosevelt’s attention shifted to urgent—but more conventional—military matters. Roosevelt convened a special session of Congress and urged repeal of an arms-embargo provision in the US Neutrality Act. When passed on November 4, the amendment authorized the United States to extend “cash and carry” arms sales to countries in a state of war.
German military advances on the ground and in the air were matched by progress in the laboratory as teams of scientists worked on atomic weapons research. There was even a detailed “Preparatory Work Plan for Initiating Experiments on the Exploitation of Nuclear Fission”38 In the United States, on the other hand, the only progress was in print, where two scientists from Washington—R. B. Roberts of the Department of Terrestrial Magnetism (DTM) and J. B. H. Kuper of the Washington Biophysical Institute—published “Uranium and Atomic Power,” an article in the Journal of Applied Physics that summarized publicly what was then known about fission. They cited Einstein’s E = mc2 equation in the first sentence as the equivalence for “releasing atomic energy to furnish a new source of power,” noted that fission was much more likely from slow neutrons than fast ones, and concluded “that the requisite conditions for a chain reaction were satisfied.”
To Lindbergh, Szilard wrote that they had once met “at lunch about seven years ago at the Rockefeller Institute, but assume that you do not remember me, and I am therefore enclosing an introduction from Prof. Albert Einstein.” Politely understated but forceful, Einstein’s letter asked Lindbergh “to receive my friend Dr. Szilard and to consider carefully what he has to tell you.” The subject, he warned, “may seem fantastic to a man not involved with science” but deserves attention “in the public interest.”39 Szilard’s letter invited Lindbergh to meet with him to discuss how “large quantities of energy would be liberated” by a “nuclear chain reaction.” Szilard also wanted to discuss how “to make an attempt to inform the administration. . . .”
But five weeks later, after Lindbergh, an isolationist, denounced Roosevelt’s efforts to sell arms abroad, Szilard sent Einstein a caustic note. “I am afraid he is not our man,” Szilard reported. Lindbergh’s public discussion of the president’s call for changes in the Neutrality Act “is on a pitiful level,” Szilard wrote. “At that one becomes kindly disposed toward Lindbergh for he at least emits human sounds.” In this note to Einstein, Szilard went on to predict “that Belgium will be overrun one of these days” and urged that they try to buy “at least 50 tons of uranium oxide” privately. “Whether I will be able to persuade a government agency to take such a step I do not know of course,” Szilard concluded. “Perhaps one would have more luck with a smart speculator.”40
At the same time, Wigner heard from Szilard that he wanted to approach Karl T. Compton at MIT, to act not only as a middleman to the president but also as a host for large-scale uranium experiments. Wigner was alarmed, fearing that Compton might find Szilard’s style disconcerting. Put whatever you would tell Compton into a memo, Wigner urged Szilard, because “from a conversation with you” he “would probably obtain only a somewhat confused picture. . . .”41
Throughout the summer and fall Szilard pursued the separate mission of finding pure graphite for his “large-scale” experiment. He exchanged dozens of letters with chemical, carbon, and metallurgical companies, visited their offices every few days, and with the help of friends and consultants pressured manufacturers to bid on contracts for tons of fresh material. Szilard’s correspondence for this period reveals that he held potential contractors to the most precise measurements and standards he could devise.42 Already concerned that even slight impurities in the uranium and graphite might absorb neutrons, Szilard was, in fact, creating a decisive difference between US and German nuclear efforts.
Repeated calls to Roosevelt’s secretary finally gained Sachs a meeting with the president on October 11. For this Sachs toted into the White House a note of his own, Einstein’s letter, Szilard’s technical memorandum, and an armload of scientific papers on nuclear fission. He may have expected to be ushered right in to see Roosevelt, but he first met Gen. Edwin M. (“Pa”) Watson, the president’s secretary, who asked Sachs to brief two ordnance experts, army colonel Keith F. Adamson and navy commander Gilbert C. Hoover. When they heard Sachs and saw his documents, the two nodded to Watson, who led him into the Oval Office.
“Alex, what are you up to?” Roosevelt asked, gazing at the papers cradled in his arms.43 At first, Sachs didn’t say, but sat across the large desk from Roosevelt and read from his own note, which warned about the possibility that a new energy source could be made into powerful bombs—a grandiose rendering of the Einstein letter. Then Sachs began reading from the technical papers heaped on his lap. When Roosevelt showed some discomfort and impatience, Sachs finally drew out Einstein’s letter and read aloud the first and last paragraphs, which referred to uranium as a “new and important source of energy” but made no mention of a “nuclear chain reaction” or the “extremely powerful” bomb that might destroy a “whole port together with some of the surrounding territory.” The paragraphs Sachs read did mention German research but not the request that “government departments” be alert to uranium ore supplies and follow experimental work by physicists.
Seeming preoccupied, Roosevelt asked Sachs to come back the next day. All this scientific talk seemed “premature” to the head of the US government.
Sachs left the Oval Office unsure about his effect and fearful he would have no second chance.44 But the next morning Roosevelt was more chipper.
“What bright idea have you got now?” he asked, and “How much time would you like to explain it?” Again they talked about Einstein’s warning, which Roosevelt seemed to have thought about overnight. Sachs still sounded vague and pompous, but Roosevelt was more attentive, listened quietly, and then interrupted.
“Alex,” he said, “what you are after is to see that the Nazis don’t blow us up.”
“Precisely,” said Sachs.
Roosevelt then leaned toward his desktop intercom and called his secretary. When Watson entered, Roosevelt waved to Sachs and his lapful of papers.
“Pa, this requires action,”
Roosevelt said. But action at that point only meant that Watson should create a government advisory committee to study the problem.45 He telephoned Lyman J. Briggs, director of the National Bureau of Standards, then the government’s principal physics laboratory, and asked him to chair an Advisory Committee on Uranium. (Germany had done the same thing six months before.) Other committee members included Sachs, the ordnance experts Adamson and Hoover, and the physicists from the DTM and Bureau of Standards who had written the September summary article on “Uranium and Atomic Power.”46 Szilard, Wigner, and Teller were also invited. Finally, it seemed to the three Hungarians, things were starting to happen.
On Saturday morning, October 21, Szilard and Wigner joined Sachs at the Carlton Hotel in Washington for breakfast to review strategy. Then the three appeared at the Bureau of Standards office in the Commerce Department to attend the first meeting of Briggs’s Advisory Committee on Uranium.47 Almost from the beginning Szilard guided the discussion, explaining how a chain reaction might be created with uranium oxide and graphite. If graphite moderated the neutrons, making them “slow,” Szilard said, then they might sustain a chain reaction; if too many neutrons were absorbed, nothing would happen because not enough of them would fly out to fission other atoms.
Colonel Adamson found Szilard’s science fantastic. At the army’s Aberdeen Proving Ground, he joked, “We have a goat tethered to a stick with a 10-foot rope, and we have promised a big prize to anyone who can kill the goat with a death ray. Nobody has claimed the prize yet.”48 Ignoring this, Szilard went on to tell the group that he and Fermi needed to conduct a large-scale experiment using uranium suspended in graphite to test how many neutrons the graphite absorbed—just the test he had proposed to Fermi in July.
Others at the meeting were skeptical, but Teller, pushing Szilard’s optimism a step further, guessed that the graphite and uranium needed for a large-scale experiment might cost only $6,000. Colonel Adamson scoffed. It generally takes two wars to develop a new weapon, he said; besides, it was “morale,” not research, that led to victory. Shifting in his chair, the formal and ever-polite Wigner could not contain his impatience.
“Perhaps,” he told Adamson in a high-pitched but steady voice, enunciating every syllable, “it would be better if we did away with the War Department and spread the military funds among the civilian population. That would raise a lot of morale.”49
“All right,” Adamson snapped. “You’ll get your money. . . . We do have money for this purpose.”
Szilard was astounded by the offer. He had attended the meeting only expecting to gain the government’s approval for their uranium research, which he assumed would be funded by industry, universities, or private investors. This promise of $6,000 for uranium research was the first commitment by the US government—a sum that would eventually swell to more than $2 billion before the first A-bomb was tested nearly six years later. But for the three Hungarians, all admittedly “green” in their dealings with American government, it must have seemed a glorious moment.
Indeed, that first step might never have been taken without Szilard’s constant planning and meddling. While waiting for Sachs to see the president and even after the White House decision to form a government committee, Szilard continued to approach private investors for research money. It is clear from his letters and from his account of many conversations that Szilard thoroughly enjoyed his role as an organizer and manipulator. Szilard later wrote to Einstein that he had Teller invited to the meeting because he lived in Washington and could serve to “keep contact with Briggs in a workable fashion.” After the first Uranium Committee meeting, Szilard returned to his room in the Wardman Park Hotel and wrote to Dean Pegram at Columbia. “It seems to me now,” Szilard said of Sachs, “that he is performing his task efficiently and in the right spirit, and now I am in favor of giving him a fairly free hand, and see what he can achieve.”50
Five days later, Szilard mailed Briggs a ten-page memo telling him what research was necessary to prove that uranium could produce chain reactions. He named laboratories where work could begin without attracting attention: Columbia, the DTM in Washington, the University of Virginia in Charlottesville, MIT, and Princeton. And Szilard urged that all research reports be withheld from publication, laying the groundwork for an atomic-secrets policy that in later years he would find a threat to both scientific advancement and civil liberties.
This memo to Briggs was Szilard’s blueprint for a program to begin building a bomb and the first of its kind drafted in the United States. In it Szilard offered calculations about buying uranium and graphite, along with a strategy for cornering markets without revealing the extent of government interest. He described the large and small experiments that would show whether a chain reaction might work, stressing that to learn it cannot work would be just as important.51
On November 1, the Advisory Committee on Uranium reported to the president that a chain reaction was possible but not certain. If controllable, the chain reaction might become a power source for submarines. If explosive, “it would provide a possible source of bombs with a destructiveness vastly greater than anything now known.” Briggs recommended buying what Szilard had asked for—fifty tons of uranium oxide and four tons of pure graphite. At last, Szilard thought, America was in the race for the bomb.
In some ways, Szilard ended the year 1939 much cheerier than he had begun it. Far from his gloom a year before over the apparent failure of his work on the chain reaction, Szilard could by November 1939 see that this “obsession” might soon work. He had designed a reactor— the uranium-graphite “pile”—during the summer, opened government channels for support to begin uranium research that fall, and in the process identified and united a circle of physicists who would become the core of the government’s A-bomb work. By perseverance and pluck, Szilard had alerted other physicists, and finally the president of the United States, to the fears that had afflicted him since 1933.
Szilard must have been in high spirits as he hosted a dinner at the Men’s Faculty Club of Columbia, on Morningside Drive and 117th Street, one Tuesday evening in November. Around the table were Fermi, now his intellectual admirer but still skeptical of Szilard’s personal and scientific exuberance; Pegram, a patient sponsor turned active supporter; and Sachs, who would continue to help Szilard and Einstein influence President Roosevelt.
But Szilard’s year also ended with familiar doubts and fears. He still lacked full-time employment, his affiliation with Columbia remained tenuous, and his Association for Scientific Collaboration existed only on paper and in his busy mind. Past insecurities also weighed on Szilard’s mind as he recalled his early efforts at refugee settlement in London. “Though I finally succeeded in getting a number of things done by exerting myself up to the limit of my strength I learned a lesson,” he wrote Sachs, “and now I am anxious to avoid a repetition of this experience.”52
Yet as another Christmas season approached, Szilard’s outlook remained bleak. To Benjamin Liebowitz he wrote that he had been unable to raise any private money for nuclear experiments and had to declare the $2,000 loan “a bad debt.” “Unfortunately, I have not earned anything during this year, as I was tied up with this work on uranium. It looks as though I shall not be able to earn anything next year, either. . . .”53
CHAPTER 15
Fission + Fermi = Frustration
1940–1941
For Leo Szilard, the first meeting of the federal government’s Advisory Committee on Uranium, in October 1939, was followed by “the most curious period in my life.” That meeting with military and civilian researchers—a direct result of Einstein’s letter to Roosevelt—set in motion America’s response to a possible German A-bomb. Or so Szilard thought. But for months “we heard nothing from Washington at all,” he recalled, and by February 1940 this silence was unnerving. “I had assumed that once we had demonstrated that in the fission of uranium neutrons were emitted, there would be no difficulty in getting people interested; but I was wrong.”<
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Physicist Enrico Fermi, Szilard’s research collaborator at Columbia University, “didn’t see any reason to do anything” as they awaited the Advisory Committee’s promised $6,000 for graphite and uranium. So Szilard tried to “amuse” himself by making more detailed calculations for the graphite-uranium chain-reaction method they had codesigned. On January 27, 1940, Szilard mailed himself a twenty-two-page memo on a nuclear-chain-reaction system, then the most detailed design for a nuclear reactor ever made.1
Encouraged by what he read of the uranium research by Frédéric Joliot- Curie and his Paris colleagues, Szilard went to Fermi at Columbia and found he was about to leave for California to pursue cosmic-ray studies. Over lunch the two men caught up on their doings.
“Did you read Joliot’s paper?” Szilard asked Fermi. He had.
“What did you think of it?” asked Szilard.
“Not much” replied Fermi. Szilard’s frustration surged. “I saw no reason to continue the conversation and went home,” he recalled.2 But Szilard must have been further enraged and frustrated on February 1 when, in the New York Times, he saw a Science Service dispatch from Washington on Joliot’s “announcement” that he had turned uranium into an atomic “firecracker” that might be “lighted” with neutrons.3 This report must have frightened Szilard as well, since he lived in fear that German scientists would make the same discoveries. As he had done before when in need of help, Szilard turned to the one person he trusted for honest advice: Albert Einstein. Down to Princeton he went, to his white frame house on Mercer Street, and in Einstein’s study suggested a newly aggressive approach. They had waited long enough for help from Washington. Szilard proposed “to go definitely on record that a graphite-uranium system would be chain-reacting, by writing a paper on the subject and submitting it for publication to the Physical Review.” He and Einstein should “reopen the matter with the government,” Szilard argued, with a new kind of pressure, one that amounted to political blackmail. Using this ploy, Szilard “was going to publish my results unless the government asked me not to do so and unless the government was willing to take some action in this matter.”4 Einstein thought about the plan and concurred.
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