Chicago Metallurgical Laboratory

The Chicago Metallurgical Laboratory enters the account through a landmark achievement and a contrast: Enrico Fermi’s team produced the world’s first controlled nuclear chain reaction there, while the laboratory’s well-equipped urban setting differed sharply from the improvised isolation of Los Alamos. It also stands in the background of a human divide within wartime science: in Chicago, the prospect that Germany might be ahead weighed heavily on many senior scientists; at Los Alamos, the same fear became an impetus to press forward.

A major center of wartime research

On December 2, 1942, Fermi led a team at the Chicago laboratory in conducting the first controlled nuclear chain reaction. The achievement made Chicago a crucial location in the developing effort to understand and harness fission. The account places it among the far-flung scientific sites whose work would have to be brought together to produce a usable weapon, though it does not describe the laboratory’s internal organization or assign it a specific role beyond its research and this milestone.

The chain reaction also gave Chicago a practical and symbolic significance. It demonstrated that a controlled nuclear process could be achieved, at a moment when physicists feared that German researchers might be further advanced in fission. The result did not dispel that anxiety. Rather, the possibility of a German bomb helped shape the urgency with which scientists understood their work.

Urban resources and an isolated counterpart

The contrast with Los Alamos makes the laboratory’s setting especially visible. John Manley arrived there from Chicago, a large city with an eminent university, extensive libraries, and a pool of experienced machinists, glass-blowers, engineers, and other technicians. Los Alamos, by comparison, had none of those established resources. Its new laboratory in the New Mexico wilderness initially lacked even basic equipment for producing neutrons, and its facilities had to be assembled amid the broader work of building an isolated community.

This comparison does not make Chicago simply a foil for Los Alamos: it shows how differently research could be situated. Chicago offered the infrastructure of an established urban center; Los Alamos demanded that scientists and administrators create a laboratory and community in a remote setting. The physical circumstances mattered to what could be done, and to how abruptly the new project had to improvise.

Different moods under the same wartime pressure

Fermi carried knowledge of Chicago’s achievement into the scientific discussions at Los Alamos. After attending some of Robert Serber’s lectures there, he told J. Robert Oppenheimer, “I believe your people actually want to make a bomb.” The remark registered a difference in atmosphere. Fermi had found the scientists in Chicago oddly subdued beside the exhilaration he encountered among the scientists on the Los Alamos mesa.

The contrast was not a difference in awareness of the danger. In both places, scientists understood that an atomic bomb might be possible and feared that Germany could be ahead. Many senior scientists in Chicago were troubled, even depressed, by that prospect. Under Oppenheimer’s leadership at Los Alamos, the same fear seemed to drive the group toward its work. The laboratory’s place in the account is therefore not only a location of scientific achievement, but one side of a comparison showing how setting and leadership could give a shared anxiety different force.