As Szilard circulated his petition, General Groves sought ways to take action against him. On July 4, 1945, Groves wrote to Frederick Lindemann, Lord Cherwell.
Lindemann, who was Winston Churchill's science advisor, had known of Szilard's ideas on the nuclear chain reaction long before the discovery of fission. As head of Oxford's Clarendon Laboratory, Lindemann had been Szilard's employer from 1935-1938.
Groves inquired about a meeting Szilard had requested with Lindemann when Lindemann visited Washington D.C. in 1943. If Szilard had mentioned secret information to Lindemann during this meeting, Groves could have charged Szilard with violating the Espionage Act.
Lindemann's reply, and his attached account of the meeting, also are reproduced here in full.
SECRET THIS DOCUMENT CONSISTS OF 1 PAGE(S) NO. 3 OF 3 COPIES, SERIES A 4 July 1945 The Right Honorable The Lord Cherwell War Cabinet Offices London, England Dear Lord Cherwell, I wonder if it would be taxing your memory unduly if I were to ask you to write me briefly the subjects of your discussion in your meeting with Dr. Leo Szilard in May of 1943, when you were in this country. Dr. Szilard, as you will recall, worked in the Clarendon Laboratory during the years 1935 to 1938. Frankly, Dr. Szilard has not, in our opinion, evidenced wholehearted cooperation in the maintenance of security. In order to prevent any unjustified action, I am examining all of the facts which can be collected on Dr. Szilard and I am therefore seeking your assistance. I am looking forward to the day when I will be able to see you again. Sincerely yours, L. R. GROVES Major General, USA
SECRET TOP SECRET PAYMASTER GENERAL GREAT GEORGE STREET, S.W.1. 12th July 1945 My Dear General, Thank you for your letter. I was very glad to hear from you again and to have a talk with Major Traynor who looked after me so well last autumn. I am sorry to hear that Szilard has been indiscreet. As you may wish to attach it to your file I have put my recollections of our conversation on a separate sheet. As you know he worked in my laboratory at Oxford and always had rather a bee in his bonnet about the awful implications of these matters. I cannot say that I really took his conversation very seriously, but I think the attached statement gives a fair account of its general tenour. I think from all accounts that success in your great project is on the verge of being achieved. I hope I may add my congratulations on the unequalled effort in which you have played such a remarkable part. If I could manage it, I should very much like to come over to America again before the year is out and if so I should look forward to seeing you again. But perhaps you will be able to get away yourself and come over here for your long promised visit before then. With kindest regards believe me yours very sincerely Cherwell P.S. I hope your daughter's tennis is making good progress.
SECRET TOP SECRET PAYMASTER GENERAL GREAT GEORGE STREET, S.W.1 CONVERSATION WITH DR. SZILARD, MAY 1943, WASHINGTON D.C. When I spoke to Szilard in Washington in 1943, he was, so far as I can remember, mainly concerned with a topic which has inflamed so many scientists' minds, namely what sort of arrangements could be made to prevent an arms race with all the disastrous consequences to which this would lead. I do not recall that he offered any solution, although when we had discussed the same matter in Oxford before the war he had advocated some agreement between scientists not to lend themselves to any application of nuclear chain reactions to lethal purposes. My impression is that his security was good to the point of brusqueness. He did, I believe, complain that compartmentalism was carried to undue lengths in America, but on the other hand, when I asked him about some point - I forget what - deriving from our work in Oxford he replied that he was not at liberty to discuss it as he had passed into the employment of the American Government. We did not, so far as I can recollect, have any further conversation on technical processes, but he kept harking back to his general anxiety about the future of the world. Cherwell
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