Szilard was so annoyed at Rutherford's dismissal that, on the same day, he conceived of the idea of nuclear chain reaction (analogous to a chemical chain reaction), using recently discovered neutrons. The idea did not use the mechanism of nuclear fission, which was not yet discovered, but Szilard realized that if neutrons could initiate any sort of energy-producing nuclear reaction, such as the one that had occurred in lithium, and could be produced themselves by the same reaction, energy might be obtained with little input, since the reaction would be self-sustaining. Szilard filed for a patent on the concept of the neutron-induced nuclear chain reaction in 1933, which was granted in 1936. Under section 30 of the "Patents and Designs Act" (1907, UK), Szilard was able to assign the patent to the British Admiralty to ensure its secrecy, which he did. Consequently, his patent was not published until 1949 when the relevant parts of the "Patents and Designs Act" (1907, UK) were repealed by the "Patents Act" (1949, UK). Richard Rhodes described Szilard's moment of inspiration: