Editing Manhattan Project (section)

=== Proposals ===
[[File:Lawrence Compton Bush Conant Compton Loomis 83d40m March 1940 meeting UCB.JPG|thumb|March 1940 meeting at Berkeley, California: [[Ernest O. Lawrence]], [[Arthur H. Compton]], [[Vannevar Bush]], [[James B. Conant]], [[Karl T. Compton]], and [[Alfred Lee Loomis|Alfred L. Loomis]]|alt=Six men in suits sitting on chairs, smiling and laughing]]
The S-1 Committee meeting on 18 December 1941 was "pervaded by an atmosphere of enthusiasm and urgency"<ref>{{harvnb|Jones|1985|p=35}}.</ref> in the wake of the [[attack on Pearl Harbor]] and the [[United States declaration of war on Japan]] and [[United States declaration of war on Germany (1941)|on Germany]].<ref>{{harvnb|Williams|1960|pp=3–4}}.</ref> Work was proceeding on three techniques for [[isotope separation]]: Lawrence and his team at the [[University of California]] investigated [[electromagnetic separation]], [[Eger Murphree]] and [[Jesse Wakefield Beams]]'s team looked into [[gaseous diffusion]] at [[Columbia University]], and [[Philip Abelson]] directed research into [[Thermophoresis|thermal diffusion]] at the [[Carnegie Institution of Washington]] and later the [[Naval Research Laboratory]].<ref name="Jones, pp. 37-39" /> Murphree also headed an unsuccessful separation project using [[gas centrifuge]]s.<ref>{{harvnb|Nichols|1987|pp=32}}.</ref>

Meanwhile, there were two lines of investigation into [[nuclear reactor technology]]: [[Harold Urey]] researched [[heavy water]] at Columbia, while Arthur Compton organized the [[Metallurgical Laboratory]] in early 1942 to study plutonium and reactors using [[nuclear graphite|graphite]] as a [[neutron moderator]].<ref>{{harvnb|Jones|1985|pp=35–36}}.</ref> The S-1 Committee recommended pursuing all five technologies. This was approved by Bush, Conant, and [[Brigadier General (United States)|Brigadier General]] [[Wilhelm D. Styer]], who had been designated the Army's representative on nuclear matters.<ref name="Jones, pp. 37-39" />

Bush and Conant then took the recommendation to the Top Policy Group with a budget proposal for $54&nbsp;million for construction by the [[United States Army Corps of Engineers]], $31&nbsp;million for research and development by OSRD and $5&nbsp;million for contingencies in fiscal year 1943. They sent it on 17 June 1942, to the President, who approved it by writing "OK FDR" on the document.<ref name="Jones, pp. 37-39">{{harvnb|Jones|1985|pp=37–39}}.</ref>