Serbian-American inventor and engineer Nikola Tesla (1856 - 1943, blurred at centre) performs an electrical experiment for writer Samuel Langhorne Clemens, aka Mark Twain (1835 - 1910, left) and actor Joseph Jefferson (1829 - 1905), 1894. They are at Tesla's laboratory at 35 South Fifth Avenue, New York City, and an electrical current is being passed through Twain and Jefferson, in order to illuminate a lamp. (Photo by Kostich/FPG/Archive Photos/Getty Images)
