Phoebe Sarah Marks was born in Portsea, England in 1854. She changed her first name to Hertha when she was a teenager. After passing the Cambridge University Examination for Women with honors in English and mathematics, she attended Girton College at Cambridge University, the first residential college for women in England. Charlotte Scott also attended Girton at this time, and she and Marks helped form a mathematics club to “find problems for the club to solve and ‘discuss any mathematical question that may arise'” . Marks passed the Mathematical Tripos in 1880, although with a disappointing Third Class performance. Because Cambridge did not confer degrees to women at this time, just certificates, she successfully completed an external examination and received a B.Sc. degree from the University of London.
From 1881 to 1883, Marks worked as a private mathematics tutor, as well as tutoring other subjects. In 1884 she invented a draftsman’s device that could be used for dividing up a line into equal parts as well as for enlarging and reducing figures. She was also active in devising and solving mathematical problems, many of which were published in the Mathematical Questions and Their Solutions from the “Educational Times”. Tattersall and McMurran write that “Her many solutions indicate without a doubt that she possessed remarkable geometric insight and was quite a clever student of mathematics.”
Marks began her scientific studies by attending evening classes in physics at Finsbury Technical College given by Professor William Ayrton, whom she married in 1885. She assisted her husband with his experiments in physics and electricity, becoming an acknowledged expert on the subject of the electric arc. She published several papers from her own research in electric arcs in the Proceedings of the Royal Society of London and The Electrician, and published the book The Electric Arc in 1902. According to Tattersall and McMurran,