William E. Ayrton was an English electrical engineer and physicist. He was educated at University College, London, where he obtained a Bachelor of Arts (BA) degree in 1867. Thereafter he studied electricity under Lord Kelvin at Glasgow. He worked in the Indian telegraph service from 1868 to 1873 and then became professor of physics and telegraphy at the Imperial Engineering College in Tokyo from 1873 to 1878. He was an active researcher during these years and, in collaboration with Professor John Perry, studied a variety of topics, including the dielectric constant and the theory of terrestrial magnetism. During these years he and Perry published more than 20 papers. In 1879 he became professor at the City and Guilds of London Institute for the Advancement of Technical Education, and in 1884 became the first professor of physics and electrical engineering at that institute's Central Technical College in London - a post in which he remained to his death in 1908. He was the author of a book on Practical electricity: A laboratory and lecture course... (London, 1887, 516p, with many later editions to 1921).
In collaboration with John Perry, Ayrton invented the surface-contact system for electrical railways in 1881, developed many portable electrical measuring instruments, and made other significant contributions to the science and practice of electricity. As early as 1879 he proposed the distribution of electrical power by means of high tension and down-transforming. Many years later, in 1905, he visited South Africa to attend the joint meeting of the British and South African Associations for the Advancement of Science. In an evening discourse delivered in Johannesburg on 29 August and dealing with "The distribution of power" he was able to point out that his early ideas on the transmission of power had been successfully implemented. Referring to the use of electricity in South Africa he opposed the idea of generating electrical power for South African use at the Victoria Falls because it would be inefficient and would spoil the beauty of the falls. His lecture was published in pamphlet form in Johannesburg. At this time Ayrton served on the Brittish Association committee investigating the construction of practical standards for electrical measurement. The committee reported at the 1905 meeting that an ampere balance had been completed and that the determination of the ampere would be made at the National Physical Laboratory in England under the supervision of Ayrton and Mr T. Mather, both of whom had played leading roles in the design of the balance.
Ayrton joined the British Association as a member in 1877, served as president of its Section A (mathematical and physical sciences) in 1898, and was a joint vice-president of this section during the Association's 1905 visit to South Africa. He was elected a fellow of the Royal Society in 1881, was president of the (British) Institution of Electrical Engineers in 1892, and president of the Physical Society during 1890-1892. As a pioneer in electrical engineering he published numerous papers, many of them in collaboration with Perry, and was also a good teacher. He was a man of restless energy and varied talents.