1-152-856 - Ann Ronan Picture Library/Heritage-Images

William Edward Ayrton (1847-1908), British physicist, electrical engineer and inventor, c1890. Ayrton studied under Lord Kelvin at Glasgow. In 1873 he was appointed to the first chair in natural philosophy and telegraphy at Imperial Engineering College, Tokyo, and was appointed professor of electrical engineering at the Central Technical College, South Kensington in 1884. Ayrton was the first to advocate power transmission at high voltage, and in collaboration with John Perry he invented electrical measuring instruments including the spiral-spring ammeter and the wattmeter. The ammeter (ampere meter) was one of the first to measure current and voltage reliably. Ayrton and Perry also worked on railway electrification, produced a dynamometer and developed the first electric tricycle. Ayrton worked on the electric searchlight with his second wife Phoebe Marks, who later became famous for her work on the electric arc.