Arthur Edwin Kennelly

Arthur Edwin Kennelly (1861-1939) was an electrical engineer born in Colaba near Bombay, India, to an Irish naval officer. He left school at thirteen, taught himself physics while working as a telegrapher, and went on to serve as an electrician on cable ships before moving to the United States in 1887 to work in Thomas Edison's West Orange laboratory. From 1894 he practised as a consulting engineer, later forming the firm Houston and Kennelly in Philadelphia, and he taught electrical engineering at Harvard University and the Massachusetts Institute of Technology. He is remembered for two things. In 1902, independently of Oliver Heaviside, he proposed that a layer of ionized gas high in the atmosphere reflects radio waves, which explained how Marconi's transatlantic signals travelled so far; it was long called the Kennelly-Heaviside layer. He also published the paper Impedance, which applied complex numbers to Ohm's law in alternating-current circuits. He presided over both the American Institute of Electrical Engineers and the Institute of Radio Engineers and received the AIEE Edison Medal.