Edward Weston, English-born inventor, early 20th century.
© Science Museum / Science & Society Picture Library
Portrait of Edward Weston (1850-1936), naturalized American inventor. Weston was noted for his contribution to the technology of electrical measurements, including the invention of a moving -coil voltmeter and the Weston standard cell invented in 1892, based on mercury and cadmium. This replaced the Clark cell as a voltage reference source, and the Weston cell became the recognized standard at the International Conference on Electrical Units and Standards in London in 1908.