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,