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Manhattan Project History

Manhattan Project History

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.

MAUD Committee Report

1. General Statement

Work to investigate the possibilities of utilizing the atomic energy of uranium for military purposes has been in progress since 1939, and a stage has now been reached when it seems desirable to report progress.

Frisch-Peierls Memorandum

The attached detailed report concerns the possibility of constructing a “super-bomb” which utilizes the energy stored in atomic nuclei as a source of energy. The energy liberated in the explosion of such a super-bomb is about the same as that produced by the explosion of 1000 tons of dynamite. This energy is liberated in a small volume, in which it will, for an instant, produce a temperature comparable to that in the interior of the sun. The blast from such an explosion would destroy life in a wide area.

Bush-FDR Letter


Vannevar Bush
March 9, 1942

The President,
The White House,
Washington, D.C.

Dear Mr. President:

On October 9, 1941, Mr. [Henry] Wallace and I presented to you the status of research in this country and Great Britain on a possible powerful explosive.

In accordance with your instructions, I have since expedited this work in every way possible. I now attach a brief summary report of the status of the matter.