描述Einstein-Roosevelt-letter.png	English: Scan of the letter sent to U.S. President Franklin D. Roosevelt on August 2, 1939, was signed by Albert Einstein but largely written by Hungarian physicist Leo Szilard. For more information on the letter and its context see its entry at the English Wikipedia.
来源	Franklin D. Roosevelt Presidential Library & Museum 4079 Albany Post Road Hyde Park, NY 12538 http://www.fdrlibrary.marist.edu/psf/box5/a64a01.html http://www.fdrlibrary.marist.edu/psf/box5/a64a02.html
作者	阿尔伯特·爱因斯坦  (1879–1955)       其他姓名 爱因斯坦; Albert Einstein 描述 德国-美国物理学家 He became famous for developing his theory of relativity, especially the equivalence of mass and energy, expressed by the most famous physical formula of the world E = mc². 出生/逝世日期 1879年3月14日  1955年4月18日  出生/逝世地点 乌尔姆  普林斯顿  工作时期 1900-1955 工作地点 苏黎世, 瑞士; 伯尔尼, 瑞士; 布拉格, Category:奥匈帝国; 柏林, 德意志帝国; 帕萨迪纳, 美国; 普林斯顿, 美国 规范控制 : Q937 VIAF: 75121530 ISNI: 000000012281955X ORCID: 0000-0001-9183-9538 ULAN: 500240971 Open Library: OL3175986A WorldCat creator QS:P170,Q937

Sir:

Some recent work by E. Fermi and L. Szilard, which has been communicated to me in manuscript, leads me to expect that the element uranium may be turned into a new and important source of energy in the immediate future. Certain aspects of the situation which has arisen seem to call for watchfulness and, if necessary, quick action on the part of the Administration. I believe therefore that it is my duty to bring to your attention the following facts and recommendations:

In the course of the last four months it has been made probable - through the work of Joliot in France as well as Fermi and Szilard in America - that it may become possible to set up a nuclear chain reaction in a large mass of uranium, by which vast amounts of power and large quantities of new radium-like elements would be generated. Now it appears that almost certain that this could be achieved in the immediate future.

This new phenomenon would also lead to the construction of bombs, and it is conceivable - but much less certain - that extremely powerful bombs of a new type may thus be constructed. A single bomb of this type, carried by boat and exploded in a port, might very well destroy the whole port together with some of the surrounding territory. However, such bombs might very well prove to be too heavy for transportation by air.

-2-

The United States has only very poor ores of uranium in moderate quantities. There are some good ores In Canada and the former Czechoslovakia, while the most important source of uranium is Belgian Congo.

In view of the situation you may think it desirable to have some permanent contact maintained between the administration and the group of physicists working on chain reactions in America. One possible way of achieving this might be for you to entrust with this task a person who has your confidence and who could perhaps serve in an inofficial capacity. His task might comprise the following:

a) to approach Government Departments, keep them informed of the further development, and put forward recommendations for government action, giving particular attention to the problem of securing a supply of uranium ore for the United States;

b) to speed up the experimental work, which is at present being carried on within the limits of the budgets of University laboratories, by providing funds, if such funds be required, through his contacts with private persons who are willing to make contributions for this cause, and perhaps also by obtaining the cooperation of industrial laboratories which have the necessary equipment.

I understand that Germany has actually stopped the sale of uranium from the Czechoslovakian mines which she has taken over. That she should have taken such early action might perhaps be understood on the ground that the son of the German Under–Secretary of state, von Weiszäcker, is attached to the Kaiser-Wilhelm-Institut in Berlin where some of the American work on uranium is now being repeated.

View Roosevelt's response of October 19, 1939

The Einstein letter was published in 1945, as part of the Smyth Report, without a copyright notice. It is thus in the public domain in the USA.

本作品在美国属于公有领域，因为其于1929至1977年（包括）间在美国出版，且没有著作权声明。更多详情，请参见共享资源:赫特图表以及公共艺术品“出版”的详细说明。请注意此作品在对美国作品不适用较短期限法则的管辖区可能仍然受版权保护（基于作者的逝世日期），例如加拿大（作者逝世后50年）、中国大陆（作者逝世后50年，不包括香港和澳门）、德国（作者逝世后70年）、墨西哥（作者逝世后100年）、瑞士（作者逝世后70年）及其他有本地条约的国家。 العربية ∙ беларуская (тарашкевіца) ∙ čeština ∙ Deutsch ∙ Ελληνικά ∙ English ∙ español ∙ français ∙ Bahasa Indonesia ∙ italiano ∙ 日本語 ∙ 한국어 ∙ македонски ∙ Nederlands ∙ português ∙ русский ∙ sicilianu ∙ slovenščina ∙ ไทย ∙ Tiếng Việt ∙ 中文（简体） ∙ 中文（繁體） ∙ +/−