Hertha Marks Ayrton, born Phoebe Sarah Marks on April 28, 1854, in Portsea, Portsmouth, England, was a trailblazing British physicist, mathematician, electrical engineer, inventor, and suffragist. Overcoming barriers of gender, class, and religion in the Victorian and Edwardian eras, she became the first woman nominated for fellowship in the Royal Society, the first to read a paper before it, and a recipient of its Hughes Medal. She registered 26 patents, advanced understanding of electric arcs and fluid dynamics, and invented practical devices, including one that aided soldiers in World War I. Her life exemplified determination, intellectual rigor, and advocacy for women in science and society.
Ayrton’s early life was marked by hardship and resilience. The third of eight children (with more expected at her father’s death), she was born to Levi Marks, a Polish-Jewish immigrant clockmaker and jeweler who fled anti-Semitic persecution, and Alice Theresa Moss, a seamstress. Levi died in 1861 when Sarah (as she was then known) was seven, leaving the family in debt. Her mother supported them through needlework and civic efforts. At age nine, Sarah moved to London to live with her maternal aunt Marion Hartog, who ran a school with her husband. There, she received a broader education than typical for girls, learning mathematics and Latin from her cousins alongside French and music.
At sixteen, she began working as a governess in London, sending money home to support her family. She adopted the name “Hertha” after the earth goddess in Algernon Swinburne’s poem, influenced by friends like Ottilie Blind, and renounced Judaism to become an agnostic while remaining proud of her Jewish heritage. Her fiery personality showed early; she once went on a two-day hunger strike at school over an unjust accusation.
Hertha’s path to higher education was challenging. With support from feminist networks, including Barbara Leigh Smith Bodichon (co-founder of Girton College), she passed the Cambridge University Examination for Women in 1874 with honors in English and mathematics. Bodichon and others funded her studies. In 1876, she entered Girton College, Cambridge, studying mathematics under coach Richard Glazebrook. Women could not receive full degrees from Cambridge at the time, so she sat the Mathematical Tripos in 1880–1881 (placing around 15th–16th in the informal rankings) and earned a B.Sc. externally from the University of London in 1881.
At Girton, she demonstrated ingenuity and leadership. She invented a sphygmomanometer (pulse recorder), founded the fire brigade, led the choral society, and co-founded a mathematical club with Charlotte Scott. She also formed friendships with prominent figures; George Eliot reportedly modeled the character Mirah in Daniel Deronda partly on her.
After university, Hertha taught mathematics, did embroidery, and ran a club for working girls while caring for an invalid sister. In 1884, she patented her first major invention: a line-divider (or draftsman’s dividing instrument) for dividing lines into equal parts and scaling figures. Useful for artists, architects, and engineers, it was exhibited at the Exhibition of Women’s Industries and patented in Britain and the US (with financial help from Bodichon and others). This was the first of 26 patents over her lifetime: five on mathematical dividers, 13 on arc lamps and electrodes, and others on air propulsion.
That same year, she attended evening classes in electricity at Finsbury Technical College, taught by Professor William Edward Ayrton, a pioneering electrical engineer and Fellow of the Royal Society. They married in 1885. Their daughter, Barbara Bodichon Ayrton (later a Labour MP), was born in 1892. Hertha initially assisted her husband but soon pursued independent research, particularly on electric arcs used in lighting.
Electric arcs were prone to flickering, hissing, and instability. Through meticulous experiments, Hertha identified the cause as oxidation of the positive carbon electrode. She proposed electrode shape changes and conditions to minimize hissing, developing what became known as the Ayrton equation relating arc length, pressure, and potential difference. Her 1895 series of articles in The Electrician detailed this work. In 1899, she presented “The Hissing of the Electric Arc” to the Institution of Electrical Engineers (IEE)—the first woman to read a paper there—and became its first female member, winning a prize. She also demonstrated at Royal Society events and spoke at the 1900 International Electrical Congress in Paris. Her 1902 book The Electric Arc became a standard reference.
In 1901, while her husband recovered at the seaside in Margate, Hertha studied sand ripples formed by waves. She conducted hydrodynamic experiments (using baths and tins) showing vortices caused ripple formation and growth. In 1904, she became the first woman to read her own paper—“The Origin and Growth of Ripple-mark”—before the Royal Society. Nominated for Fellowship in 1902, she was rejected on the technicality that married women lacked separate legal personhood under the Society’s charter. However, in 1906, the Royal Society awarded her the Hughes Medal for her work on electric arcs and sand ripples—one of the first women so honored.
After William’s death in 1908, Hertha continued research on hydrodynamics and air flow. During World War I, she applied vortex principles to invent the “Ayrton fan” (or flapper): a hand-held device of waterproof canvas on a cane frame with a hickory handle. It dispersed poison gas from trenches by creating air impulses. Initially dismissed by the War Office, public pressure led to about 104,000 units being produced and issued. She later adapted versions for mines and sewers.
Ayrton was deeply involved in the suffrage movement. She joined the Women’s Social and Political Union (WSPU) in 1907, donating generously (over £1,000 in some years) and hosting recovering hunger-striking suffragettes like Emmeline Pankhurst. She chaired the physical sciences section at the 1899 International Congress of Women and advocated for women’s education and rights. She defended Marie Curie publicly when credit for radium was misattributed to Pierre, famously stating: “An error that ascribes to a man what was actually the work of a woman has more lives than a cat.” She helped found the International Federation of University Women (1919) and the National Union of Scientific Workers (1920).
Hertha Ayrton died on August 26, 1923, in North Lancing, Sussex, from blood poisoning after an insect bite, at age 69. Her legacy endures through her scientific contributions—pioneering work relevant to plasma physics, fluid dynamics, and engineering—and her role in opening doors for women. A blue plaque marks her London home; the Hertha Ayrton Research Fellowship at Girton continues; and she is remembered as one of Britain’s most influential women in science.
Hertha Marks Ayrton’s career illustrates how talent, mentorship, and perseverance can overcome systemic barriers. In an era when women were often sidelined or credited through male relatives, she insisted on recognition through patents, publications, and presentations. Her inventions improved lighting and saved lives; her research advanced fundamental understanding; and her activism advanced equality. As she noted, science should judge work on merit, not sex. Her story inspires continued efforts toward inclusive scientific communities, proving one woman’s ripples of influence can grow into lasting waves of change.