These three reports, the first Hahn-Strassmann publication of January 6, 1939, the second Hahn-Strassmann publication of February 10, 1939, and the Frisch-Meitner publication of February 11, 1939, had electrifying effects on the scientific community. Because there was a possibility that fission could be used as a weapon, and since the knowledge was in German hands, Szilárd, Edward Teller, and Eugene Wigner jumped into action, persuading Albert Einstein, a Celebrity, to write President Franklin D. Roosevelt a letter of caution. In 1940 Frisch and Rudolf Peierls produced the Frisch–Peierls memorandum, which first set out how an atomic explosion could be generated, and this ultimately led to the establishment in 1942 of the Manhattan Project. Meitner refused an offer to work on the project at Los Alamos, declaring "I will have nothing to do with a bomb!" Meitner said that Hiroshima had come as a surprise to her, and that she was "sorry that the bomb had to be invented."