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Manhattan Project Scientists & Leaders

Manhattan Project Scientists & Leaders

Szilard Petition


July 17, 1945

Discoveries of which the people of the United States are not aware may affect the welfare of this nation in the near future. The liberation of the atomic power which has been achieved places atomic bombs in the hands of the Army. It places in your hands, as Commander-in-Chief, the fateful decision whether or not to sanction the use of such bombs in the present phase of the war against Japan.

Interim Committee Report

Science Panel's Report to the Interim Committee

June 16, 1945



You have asked us to comment on the initial use of the new weapon. This use, in our opinion, should be such as to promote a satisfactory adjustment of our international relations. At the same time, we recognize our obligation to our nation to use the weapons to help save American lives in the Japanese war.

Bohr's Safety

201 Baker, Nicholas,

5 February 1944.



Dr. R. C. Tolman,

Office of Scientific Research & Development,

Washington, D. C.

Subject: Nicholas Baker.

1. At the conclusion of a recent report of the technical surveillance of the Bakers, the reporting agent made the following comment:

Hyde Park Aide-Mémoire

1. The suggestion that the world should be informed regarding tube alloys, with a view to an international agreement regarding its control and use, is not accepted. The matter should continue to be regarded as of the utmost secrecy; but when a “bomb” is finally available, it might perhaps, after mature consideration, be used against the Japanese, who should be warned that this bombardment will be repeated until they surrender.

Feynman on Los Alamos

From Los Alamos From Below by Richard Feynman

I was working in my office one day, when Bob Wilson came in. I was working—[laughter] what the hell, I’ve got lots funnier yet; what are you laughing at?—Bob Wilson came in and said that he had been funded to do a job that was a secret and he wasn’t supposed to tell anybody, but he was going to tell me because he knew that as soon as I knew what he was going to do, I’d see that I had to go along with it. 

Greenewalt on Chicago Pile-1

On Wednesday afternoon, 12/2/42, Compton took me over to West Stands to see the crucial experiment on Pile #1. When we got there, the control rod had been pulled out to within 3 inch of the point where K would be 1.0. The rod had been pulled out about 12 inch to reach this point. The resultant effects were being observed 1) by counting the neutrons as recorded on an indium strip inside the pile (see previous notes) and 2) on a recorder connected to an ionization chamber placed about 24 inch from the pile wall. The pile itself was encased in a balloon cloth envelope.

Fermi on Chicago Pile-1

From Fermi's Own Story by Enrico Fermi

The year was 1939. A world war was about to start. The new possibilities appeared likely to be important, not only for peace, but also for war. A group of physicists in the United States—including Leo Szilard, Walter Zinn, now director of Argonne National Laboratory, Herbert Anderson, and myself—agreed privately to delay further publications of findings in this field.