William Edward Ayrton

William Edward Ayrton
Death date
Fields of study


William Edward Ayrton was a British electrical engineer and physicist known for his contributions to electrical measuring instruments and for the development of technological infrastructure in India and Japan.

Ayrton was born in 1847 to a well-connected London family. His father, a noted barrister and linguist, pushed him to excel in school, where he won scholarships in mathematics. These scholarly achievements led to a year-long fellowship to study electrical theory and laboratory technique with Sir William Thomson (later Lord Kelvin) at the University of Glasgow in 1867. Following a subsequent year of study in Europe, he went to India, where he helped develop a system for identifying faults in overland telegraph lines being strung across this British colony.

In 1873, he and his first wife, Matilda, moved to Japan, where the modernizing Meiji government hired him to teach physics and telegraphy at Tokyo’s Imperial College of Engineering. He developed a contested relationship with the Meiji leadership, promoting independent research by his Japanese students while also insisting that foreign supervision was necessary to operate its national telegraph system. Although his five-year contract was not renewed, Ayrton remained celebrated for opening Japan’s first public electric lighting system at Tokyo’s central telegraph station in 1878.

He returned to London in 1879 and took a professorship of physics at Finsbury, applying a model of technical education that proved very popular. Along with teaching, he worked with long-time collaborator John Perry on practical applications of electromagnetism. They developed a number of devices—the ammeter and the wattmeter—that allowed for the direct-reading of electrical output and resistance, along with a clock-based domestic electricity meter. They also pioneered electric transportation systems, such as the first electric tricycle and the block contact switching system, which prevented two electric trains from sharing the same stretch of track.

His second wife was Hertha Marks Ayrton. They married in 1885 and collaborated on many research projects. Hertha Ayrton became the first female member of the Institution of Electrical Engineers.

Ayrton continued to teach, with the requirement that his work could not include commercial consulting. He also served on various English scientific societies and was often hired as an expert witness in patent disputes. He died in 1908.

Further Reading

Yuzo Takahashi, "William Edward Ayrton at the Imperial College of Engineering in Tokyo--The First Professor of Electrical Engineering in the World," IEEE Transactions on Education, Vol. 33, No. 2 (May 1990).