The Manhattan Project

by Cynthia C. Kelly

  Even though he regarded an atomic explosion as “remote from a practical standpoint,” Bush still wished “there were no such thing” as fission. When he met Roosevelt in early June 1940 to gain the president’s approval for NDRC, the two men apparently never mentioned fission research. But in subsequently working out details of NDRC’s operation with White House aides, Bush asked to have responsibility for the uranium committee. No one objected, and he took it over.

  While Bush had ceded power by giving the Army management of the bomb project, it had not been a hasty decision. As far back as December 1941, he had voiced his preference for the Army to assume responsibility for making an atomic bomb when “full-scale construction is started.” He favored the Army because Secretary of War Stimson, the departmental staff, and top Army officers listened to him. By and large, the naval officers did not.

  The decision to exclude the Navy from the Manhattan Project was Bush’s alone. The Navy’s exclusion from the project was curious since its officers had shown an interest in fission since 1939. More technically savvy than the Army, the Navy had employed the first two people paid by the government to investigate atomic energy (albeit as a source of power for its ships). One of them was a former Carnegie Institution scientist. The Navy maintained its own modest program of atomic research during the war, but its isolation from the main action hardened the animus felt by some naval officers toward Bush. After the war, one admiral described Bush’s choice of the Army as “political chicanery” and claimed that the Navy’s exclusion slowed progress toward a bomb.

  Bush never doubted the correctness of his decision to hand the Army the entire project. Bush’s preference for a single service had its benefits. It reflected his basic view that atomic policy should be made by a small group, and he wished to avoid interservice rivalries. Besides, dealing with the Navy was a trial. Frank Knox, the department’s secretary, never called on him for advice. Ernest King, the Navy’s chief, frequently fought with Bush. Other officers saw the OSRD as a threat. The Navy’s patchwork of fiefdoms, meanwhile, did not strike Bush as well-suited to handle a massive project. He may also have thought of his tensions with the Navy before the war over his designs for code-breaking computers. He even might have recalled that during World War I the Navy had snubbed his submarine detector.

  Keeping atomic work within a single service also reduced the chances of a public discussion about atomic weaponry. Bush periodically reminded the military’s censors of the need to maintain a press ban on the subject. He even saw “a certain amount of harm” in a few newspaper reports on atomic energy. He feared that the media might publicize the bomb project, alerting the country’s enemies. But the press played ball. By late 1944, Bush called the cooperation “excellent,” noting that “the press on a voluntary basis has prevented the subject being widely discussed in print.”

  While Bush’s penchant for secrecy reflected Roosevelt’s own preference, the effect was to deny the public any chance to shape government policy on atomic weapons, even in a limited way. Bush also restricted the information available to his own researchers in order to limit the possible damage caused by espionage and to shield himself from criticism. This sometimes made Bush wary of enlisting the aid of certain scientists, even brilliant ones. For instance, he did not trust Einstein. Even though he had first alerted Roosevelt about the potential for an atomic bomb, Einstein was a liberal, a German and a Jew. Bush approached him cautiously. “I have a problem for Einstein,” he wrote a colleague of Einstein’s at Princeton University. “If you think that it is entirely safe to put him to work on it, won’t you please take it up with him? I have no question whatever about his loyalty, but simply some question as to his discretion. It happens that I would not wish anyone to know that this particular problem is even being worked upon. Hence what I hope is that he can go to work on it personally without communicating to his associates any more than a statement that he is working on a mathematical problem in connection with defense.”

  Harris and Ewing, News Service, Massachusetts Institute of Technology, Courtesy AIP Emilio Segre Visual Archives

  Vannevar Bush was an early proponent of uranium fission research in the United States.

  Transatlantic Travails

  At first, Sir James Chadwick, Nobel Prize–winning physicist and author of the Maud Report, was rightfully skeptical of the American effort to contribute to the development of an atomic bomb. He felt his American counterpart, Lyman Briggs, was “an inarticulate and unimpressive man.” Fortunately, Drs. Vannevar Bush and James B. Conant were quick to seize on the Maud Report and take initiative for the Manhattan Project. This account by Andrew Brown from The Neutron and the Bomb traces the rocky beginnings of the joint Anglo-American effort.

  From The Neutron and the Bomb

  BY ANDREW BROWN

  Several copies of the Maud Report were sent to the United States with the aim of fostering collaboration. One copy went to the inert Lyman Briggs, who as [physicist Mark] Oliphant subsequently discovered, locked the report in his safe without showing it to other members of his Uranium Committee. Fortunately, copies were also sent to an activist, Vannevar Bush—an inveterate inventor and academic engineer, who had persuaded President Roosevelt to place him at the head of the National Defense Research Committee (NDRC) in June 1940. By now he had become the director of a new, overarching agency, the Office of Scientific Research and Development (OSRD). Bush had been succeeded at the NDRC by James B. Conant, an organic chemist, who had visited both Oxford and Cambridge in the early 1930s, when he found himself “on the point of becoming an Anglophile.” Bush and Conant were two middle-aged Yankees who had both spent a period working as government researchers in World War I before making successful careers as academic scientists in Boston: Bush had risen to become Dean of Engineering at the Massachusetts Institute of Technology before moving to Washington in 1939, and Conant was President of Harvard University. They were alarmed by events in Europe and were opposed to the United States’ isolationist stand: they seized on the Maud Report as a realistic opportunity for a scientific project which could be developed during the present war and which the United States could not afford to ignore. Although Bush and Conant recognized the quality of the British Maud Committee and the thoroughness of their report, they decided to subject the proposals to an independent scientific review by leading American experts under the auspices of the National Academy of Sciences to establish an incontrovertible basis for future progress.

  The first response to the Maud Report from America to reach London was from Charles Darwin, now Director of the British Central Scientific Office in Washington. He had previously written in early July 1941 to report his impressions of a meeting of the Briggs Uranium Committee, which he had attended. It had lasted over five hours with hardly a mention of the salient problem of isotope separation: “The plain fact is that they are very nearly stuck on that side,” was his verdict. In a handwritten letter dated 2 August 1941 to Lord Hankey (Chairman of the Cabinet Scientific Advisory Committee), Darwin allowed himself to bring up the morality of the enterprise, something which the Maud Committee had studiously avoided. He also said that he had recently been approached by Bush and Conant on the subject of atomic bombs, and there did seem to be the promise of movement. He thought that decisions needed to be made in government circles about the large expenditures involved, and raised the question whether such a weapon would ever be used:

  Are our Prime Minister and the American President and the respective General Staffs willing to sanction the destruction of Berlin and the country round, when, if ever, they are told it could be accomplished at a single blow?

  It appears to Bush and Conant, and I concur, that the time is ripe for a full examination of whether the whole business should be continued at all.

  According to Darwin, Bush and Conant favored a joint project between the two governments; he thought it “fairly clear” that the plant would have to be built in the U.S. or Canada. Darwin recommended that a small secret
conference should be set up “with men of balanced judgment”; his suggestion for the British representatives were Chadwick, “who is an authority on the general subject of nuclear physics,” Professor Simon from Oxford, because of his expertise on isotope separation, and G.P. Thomson.

  When Roosevelt wrote to Churchill in October 1941 proposing a joint Anglo-American effort to develop the bomb, he did so after being briefed at the White House by his scientific chief Vannevar Bush. Earlier in the summer, the British scientists were puzzled by the lack of any communication from Bush or other top-ranking American scientists about the Maud Report. In late August, Mark Oliphant flew to the U.S. in an unheated bomber to discuss the latest developments in radar, and was charged by the other Maud Committee members to find out what fate had befallen their report. It was he who discovered that Lyman Briggs, “this inarticulate and unimpressive man,” had locked the papers away for security. Oliphant was “amazed and distressed” and made it his business to inform the other Uranium Committee members that the bomb should be their absolute priority. He even flew from Washington to Berkeley in order to convince [physicist Ernest] Lawrence of the crucial nature of the Maud Committee’s findings. Once persuaded, Lawrence became an irrepressible agent himself, goading other members of the American scientific elite into action. As a result of the combined lobbying, Bush decided to send two members of the Uranium Committee on a visit to Britain so that they could gather firsthand information about work in progress. The two selected were George B. Pegram, whose Columbia University department was now home to [Enrico] Fermi and [Leo] Szilard, and Harold Urey who had won the Nobel Prize for his discovery of heavy water.

  When he heard that Pegram and Urey were coming to visit England, Chadwick wrote at once to MAP [Ministry of Aircraft Production] expressing his wish to meet them. He wanted to get clear “what is being done in the U.S.A.—from reports [they] seem only interested in the boiler, not seriously considering the bomb project.” He also wanted to establish what the Americans knew of the British work: “Oliphant thinks they are not aware.” He closed his letter with a reminder about secrecy:

  There has been so much loose talk both here and in America that the enemy must be well aware that we are engaged on the uranium problem. We must take every step to prevent them from learning that we hope to proceed to a manufacturing stage.

  By the time Pegram and Urey arrived in England in October 1941, the illustrious Maud Committee had been supplanted by Tube Alloys, controlled by DSIR [Department of Scientific and Industrial Research] through the person of Wallace Akers, who had been seconded from ICI [Imperial Chemical Industries]. The transition was not handled diplomatically—some of the Maud team were not informed of the change until December and grew restive at the apparent lack of activity. Chadwick was officially informed by [Sir Edward] Appleton, the head of DSIR, on 25 October, but did not like the tone or the content of his letter. In his reply, Chadwick issued a warning against usurping the scientists’ leading role in the new organization. A few days after sending this letter, Chadwick attended the first meeting of the Technical Committee of Tube Alloys under Akers’ chairmanship; the other members of the committee were [Hans von] Halban, [Franz] Simon, [Rudolf] Peierls, and Dr. Slade—an ICI scientist.

  Chadwick’s misgivings were loudly echoed by Oliphant, who “registered a full-throated protest.” He told Appleton he could “see no reason whatever why the people put in charge of this work should be commercial representatives completely ignorant of the essential nuclear physics upon which the whole thing is based.” Oliphant communicated to Chadwick his frustration with the Tube Alloys reorganization and the reluctance of the British to commit themselves to whole-hearted partnership with the Americans.

  The Americans will undoubtedly go right ahead with both projects [bomb and boiler], and there is little doubt that they with their tremendous resources will achieve both before we have fairly begun. It seems to me far wiser to work in completely with them…

  I only hope that you the only man in the country who really understands the problem will be allowed to have a real and deep influence on the scientific development.

  Chadwick tried to convince Oliphant that the new Tube Alloy arrangement would be satisfactory, although he agreed that Appleton’s handling of the matter had been “autocratic and discourteous.” He thought there was a determination to advance the bomb project with all speed, and while he had no reservations about full collaboration with the U.S., he did not share Oliphant’s view about them finishing before we have begun: “We are some way ahead and we shall remain ahead.” This was too much for Oliphant, who replied by return:

  I still feel that you in common with many other people in this country, underestimate seriously the extent of the American effort. I am extremely sorry that you have not gone to the States yourself for I am sure the picture which one gets in that way is rather different from that obtained from visiting Americans…

  The visiting Americans, Pegram and Urey, had of course come to Liverpool to meet Chadwick, and were impressed by his near certainty that if pure 235U were made available, a bomb of devastating power could be produced within a relatively short time. By the time they returned to the U.S.A. at the end of November 1941, the Committee of the National Academy of Sciences had submitted their report to Bush, essentially confirming the positive tone of the Maud Report about a weapon based on a critical mass of 235U, predicting a “fission bomb of superlatively destructive power.” Bush sent the report to the President on 27 November, informing Roosevelt that he was forming an engineering group and organizing scientific research towards the mastery of the physical and chemical processes necessary to produce the components of the bomb, and to assemble them successfully. At this stage, as we have seen, Roosevelt had already written to Churchill with the intention of fostering an Anglo-American partnership. There was such high esteem for their British counterparts amongst the American scientists (particularly [James] Conant, Pegram and Urey who had visited wartime Britain and witnessed its siege), that Oliphant’s notion of complete co-operation was fully viable. If Chadwick had heeded his pleas and the two men together had pressed for such an arrangement, they might, by converting Lord Cherwell, have been able to persuade Churchill to overcome his own and the Chiefs of Staff’s reticence; it seems likely that Sir John Anderson would have been a supportive and influential ally. As it was, Chadwick was not yet ready to abandon his conviction that British science was as good as any in the world and could pull off this project without outside help, and he did not rally to Oliphant’s call. Indeed so deaf was he to Oliphant’s entreaties that in early 1942, when Akers led a party of scientists from the Technical Committee of Tube Alloys (Simon, Halban and Peierls) to the U.S., Chadwick chose to remain in England. The British visitors were given free range over the burgeoning American programme, no site was off limits to them and they were able to talk to all the American scientists they wished. The American effort under Bush was already more co-ordinated, and now the US had entered the war, it was fired with new vigour and determination. The opportunity for full partnership was already fading, and would disappear as the US Army took over control from the scientists and millions of taxpayers’ dollars were invested in a secret, all out, effort.

  Whereas the National Academy of Science Committee, like the Maud Committee before them, had concentrated almost exclusively on the prospect of separated 235U as material for the bomb, work had continued at Berkeley on element 94 (plutonium). Lawrence, together with Arthur Compton from Chicago, convinced Bush and Conant that this newly created element might offer the shortest route to a bomb and should not just be considered as potential fuel for energy production. Chadwick had supported the Cavendish work on plutonium, and a year earlier had raised the relative merits of the two materials with G. P. Thomson. In January 1941, he told Thomson that on his calculations of neutron cross-sections for 235, 94 was not likely to be more potent than 235, but might be just as good, and the choice between them would depend on the relative
ease of preparation. He had then been forced by limited resources to concentrate on 235U; now the Americans decided to broaden the experiment to include element 94 so that from the beginning of 1942, there were two types of bomb in prospect. Lawrence and Compton immediately organized teams of scientists to pursue both alternatives with early promising results. Seaborg continued his work on element 94 and in a secret report with [Isadore] Perlman in November, described how they had managed to produce microgram quantities of the substance by bombarding uranium with high-energy deuterons. They also devised several chemical processes by which element 94 could be extracted from the uranium and fission products of a reacting nuclear pile. Their studies on microscopic quantities of plutonium showed that its fission properties “are somewhat superior to those of 235U for the object in mind.”

  In the spring of 1942, Bush approached the US Army to provide the gigantic engineering support that was going to be necessary to translate the scientists’ predictions into a usable weapon. By June, the US Army was responsible for “all large-scale aspects” of the atomic energy programme, and the Manhattan Project was born. The OSRD would continue to direct the scientific research, now with a budget of US$31 million for the fiscal year 1943 and Bush’s forceful recommendation to the Secretary of War, Henry Stimson, that “nothing should stand in the way of putting this whole affair through to conclusion, on a reasonable scale, but at the maximum speed possible, even if it does cause moderate interference with other war efforts.”