نظرية ثابت الزمن ومتغير الطاقة

خطـاب اينشتاين الأول للرئيس روزفلت

Albert Einstein
Old Grove Rd.
Nassau Point
Peconic, Long Island

August 2nd 1939

F.D. Roosevelt
President of the United States
White House
Washington, D.C.



Sir:

Some recent work by E.Fermi and L. Szilard, which has been com-

municated to me in manuscript, leads me to expect that the element uran-

ium may be turned into a new and important source of energy in the im-

mediate 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 quant-

ities of new radium-like elements would be generated. Now it appears

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 - though much less certain - that extremely power-

ful 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 is some good ore 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 more

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 uran-

ium ore for the United States;

b) to speed up the experimental work,which is at present being car-

ried on within the limits of the budgets of University laboratories, by

providing funds, if such funds be required, through his contacts with y

private persons who are willing to make contributions for this cause,

and perhaps also by obtaining the co-operation 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 Weizsäcker, is

attached to the Kaiser-Wilhelm-Institut in Berlin where some of the

American work on uranium is now being repeated.

Yours very truly,

(Albert Einstein)