The Manhattan Project: Making the Atomic Bomb

Program Review: Summer 1941

During 1939 and 1940 most of the work done on isotope separation and the chain reaction pile was performed in university laboratories by academic scientists funded primarily by private foundations. While the federal government began supporting uranium research in 1940, the pace appeared too leisurely to the scientific community and failed to convince scientists that their work was of high priority. Certainly few were more inclined to this view than Ernest O. Lawrence, director of the Radiation Laboratory at the University of California in Berkeley. Lawrence was among those who thought that it was merely a matter of time before the United States was drawn into World War II, and he wanted the government to mobilize its scientific forces as rapidly as possible.

Bush and Lawrence met in New York City. Though he continued to support the Uranium Committee, Bush recognized that Lawrence's assessment was not far off the mark. Bush shrewdly decided to appoint Lawrence as an advisor to Briggs-a move that quickly resulted in funding for plutonium work at Berkeley and for Nier's mass spectrograph at Minnesota-and also asked the National Academy of Sciences to review the uranium research program. Headed by Arthur Compton of the University of Chicago and including Lawrence, this committee submitted its unanimous report on May 17. Compton's committee, however, failed to provide the practical-minded Bush with the evidence he needed that uranium research would pay off in the event the United States went to war in the near future. Compton's group thought that increased uranium funding could produce radioactive material that could be dropped on an enemy by 1943, a pile that could power naval vessels in three or four years, and a bomb of enormous power at an indeterminate point, but certainly not before 1945. Compton's report discussed bomb production only in connection with slow neutrons, a clear indication that much more scientific work remained to be done before an explosive device could be detonated. ¹⁴ Bush reconstituted the National Academy of Sciences committee and instructed it to assess the recommendations contained in the first report from an engineering standpoint. On July 11 the second committee endorsed the first report and supported continuation of isotope separation work and pile research for scientific reasons, though it admitted that it could promise no immediate applications. The second report, like the first, was a disappointing document from Bush's point of view. ¹⁵

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