FLEMING, SIR JOHN AMBROSE ), English physicist, was born at Lancaster on Nov. 29, 1849. He studied at London and Cambridge, and held the posts of lecturer in applied mechanics, Cambridge, and professor of electrical engineering, University college, London (1885-1926). Fleming is a pioneer in the applications of electrical science. He has carried out original investigations and has taken a prominent part in applying his and other people's researches to the development of electric lighting and wireless telegraphy and telephony. Fleming's earliest researches were on electrolysis but he soon turned his attention to the problem of the electric glow lamp of which he was one of the earliest investigators. In a large number of ways Fleming helped in the development of the practical application of the glow lamp, he installed electric lighting on one of the first ships of the Royal Navy to be so equipped. He acted in an advisory capacity from 1882 to 1894 to the Edison Electric Light company and later he was with the Edison and Swan company. Fleming also assisted various corporations in matters concerned with electric lighting.
While making investigations on the glow lamp Fleming observed phenomena which led him to a study of thermionics and in he made the first form of thermionic valve. He has helped to develop it and to make it the important instrument it now is in wireless. In addition to numerous other services to wireless, Fleming gave scientific assistance and helped with some of the constructional work on the first long-distanc,: wireless station at Poldau. He also helped in the development of telephony and in 1879 acted as scientific adviser to the Edison Telephone company which was formed to set up telephone exchanges in London. Fleming invented a cymometer to measure wave lengths and an oscillating valve detector of electric waves. In conjunction with Dewar he carried out a series of investigations on the magnetic and electric properties of metals at low temperatures.
Fleming is a member of numerous learned societies and has been awarded a number of honorary degrees. He has received the Hughes medal of the Royal Society the Albert Medal of the Royal Society of Arts (1921), and a number of other medals.
Amongst the numerous books written by Fleming are Hand book of the Electrical Laboratory and Testing Room (19o1); Waves and Ripples in Water, Air and Aether 0902); Alternate Current Transformer; Principles of Electric Wave Telegraphy (1906) ; Manual of Radiotelegraphy and Telephony (1908) ; The Thermionic Valve in Radiotelegraphy (1919) ; Fifty Years of Electricity (192I ) ; Electrons, Electric Waves and Wireless Telephony (1923) ; The Interaction of Scientific Research and Electrical Engineering (1927). He was knighted in 1929.