One of the most important figures at the turn of the 19th century and the driving force behind the popularization of electricity was without any doubt Thomas Alva Edison. His first great invention that emerged at the Menlo Park lab was the phonograph, developed to some extent by accident during works to improve the effectiveness of telegraphic transmission in 1877, instantly making its creator world-famous. Two years later Edison presented a model of a light bulb and in 1896 in New York made the first public show of his Kinetoscope. The complete list of inventions patented by Edison contains 1093 items, including: motors and generators, many types of telegraphs and telephones, railway and tramway solutions, systems for transmission and control of electric energy and many others.
Edison also invented the electric chair and was a great follower of this method of capital punishment. On 29 March 1889 a man called William Kemmler killed his common-law wife with a hatchet and was sentenced to death – the execution, using the new “humane” device from Edison’s factory, was planned to take place on 6 August. Kemmler’s advocate made an appeal arguing that this kind of death was unusually cruel, and he was supported by George Westinghouse – a backer of the use of alternating current. However, the appeal was rejected.
Edison, although he officially objected to capital punishment, supported the charge most probably since he was willing to propagate the “universal values” of direct current and to promote his patent. Kemmler survived the first 17-second application of 1000 V current, so a decision was made to increase the voltage to 2000 V. When the current was turned on again, the convict’s blood vessels ruptured, a strong odour of burning flesh could be smelled in the death chamber and several nauseated spectators tried to leave the room. The entire execution took approximately eight minutes. It was later covered in the press by a reporter who witnessed it as “an awful spectacle, far worse than hanging”. Edison’s competitor – Westinghouse – commented in a laconic but offhand manner: “They would have done better using an axe”. Nevertheless, the electric chair was adopted in the United States as a tool of capital punishment and was in common use in the following century. Outside the USA convicts were executed by electrocution in the Philippines. In the 1890s, Ethiopia also planned to introduce this method of capital punishment. However, when a transport of electric chairs arrived, it turned out that the country did not have a single power plant…
Edison, despite marginal incidents such as his ambiguous role in the execution of Kemmler, was a US hero and in 1882 it seemed that direct current would become the predominant type of energy in the future. New inventions and the infrastructure involving: power plants, transmission lines, lighting systems, and motors – all operated using direct current. Current generators were produced in industrial quantities and they could supply current according to customised needs. However, the following years were recorded in the history of power engineering industry as a period of fierce competition between two systems: direct and alternating current, and perhaps above all between two persons: Thomas Alva Edison and Nikola Tesla.