the manhattan project

The phenomenon of nuclear fission only just discovered and prompting the United States to eventually establish its own research programme, with the endorsement of Albert Einstein Hungarian physicist Szilárd Leó (*1898 - †1964) dispatched his letter to president Franklin D. Roosevelt on this day in 1939. Immediately comprehending the ramifications for energy production or warfare having conducted experiments with less fissile materials and unable to sustain a chain-reaction, Szilard first in mid-July thought to warn Belgium as their colony in the Congo held the largest known reserves of uranium and was fearful that the Germans could persuade them to part with it handily, not realising what they were trading away and had recruited Einstein to speak on his behalf through consular channels as Einstein was friends with the Belgian royal family. With the closing salutation, “Yours truly,” the letter began: 

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 almost certain that this could be achieved in the immediate future. 

Specifically citing the suspension of the sales of uranium from occupied Czechoslovakia and on-going research in German universities, Szilard further conjectured that while it probably was not feasible to miniaturise the components necessary for a nuclear reaction for portable bombs and mobile warheads, he did believe it likely that the process could be accommodated on board a ship that could attack a city from the harbour. FDR (his reply pictured) was delivered this executive summary plus a longer, more detailed explanation of the science underpinning his forewarning.