Celebrating Hertha Ayrton
Anne Locker, IET Library and Archives
In 1899 a paper on ‘The Hissing of the Electric Arc’ was presented to the Institution of Electrical Engineers (IEE, now the IET) and published in its journal. This was a first for the institution: it was a paper written and presented by a woman.
The author, Hertha Ayrton, was born Phoebe Sarah Marks in 1854.The third of a large family whose father, a Polish Jewish watchmaker, died when she was seven, she benefited from her mother’s progressive views on education. Rather than staying at home to help in the house, she was sent to live with an aunt who ran a school.
Sarah started out as a teacher and mathematics coach but was encouraged to study for entry to Girton College, Cambridge. It was at this time that a friend christened her ‘Hertha’, from a poem by Swinburne. An important benefactor was Barbara Bodichon, co-founder of Girton, who raised money for Hertha’s college fees. Barbara introduced Hertha to the novelist George Eliot and she is supposed to have partially inspired the character ‘Mirah’ in Daniel Deronda.
After graduating, Hertha returned to London to teach and met her husband William Ayrton while attending classes at Finsbury Technical College. William encouraged Hertha to continue her work after their marriage and the birth of their daughter, but it was a legacy from Barbara Bodichon which enabled her to employ a housekeeper and free up time for research.
Arc lamps were the first practical electric lamps. The light came from a bright white spark generated by an electric current travelling between two carbon rods. Sometimes these lamps made humming and hissing noises, and it was the hissing on which Ayrton focused her research. This hissing meant that the arc was becoming unstable and less efficient. Ayrton set out to study the phenomenon in painstaking detail, concluding that it was as the result of changes in the shape of the carbon ends. She stated that a) the hissing arc was caused by a crater shape forming on one side of the carbon and b) that the drop in current thus produced is due to the effect of oxygen reaching this crater and combining with the carbon on the surface.
Ayrton’s paper generated an enthusiastic response. The President, Sir Joseph Swan, stated:
“It is the first paper we have had the pleasure of receiving from Mrs Ayrton; I sincerely hope it will not be the last. We do not have the honour of numbering among us any lady members, but I do not know any legal disability against ladies becoming members. If not, I hope we may look forward to the pleasure of numbering Mrs Ayrton among the members of the Institution before long.”
Hertha Ayrton was elected as a member later that year.
Ayrton went on to publish a book on the arc lamp and extended her research to the phenomena of vortices in water and air. This research would lead to the development of the ‘Ayrton fan’, used in the First World War to expel gas from the trenches. In 1906, she was awarded the Royal Society’s Hughes medal for her research.
In 2026, there will be a series of events and activities to mark the 120th anniversary of Hertha Ayrton being awarded the Hughes Medal. If you’d like to find out more, please contact the IET Archives at archives@theiet.org.
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