X-ray crystallographer, professor, peace activist and prison visitor – Dame Kathleen Lonsdale achieved many firsts and a form of diamond is named in her honour. She proved the benzene ring was flat by X-ray diffraction methods in 1929 and was the first to use Fourier spectral methods while solving the structure of hexachlorobenzene in 1931.
As a woman scientist, she was one of the first two women elected as fellow of the Royal Society in 1945 (along with Marjory Stephenson), first woman tenured professor at University College London, first woman president of the International Union of Crystallography, and first woman president of the British Association for the Advancement of Science.
Born Kathleen Yardley to postmaster Harry Yardley and Jessie Cameron in Newbridge, Co Kildare, in 1903, she was the couple’s 10th and final child.
However, drink and irritability drove her parents apart. In 1908, Kathleen’s mother left Harry and brought the children to Seven Kings, Essex, in England.
Kathleen studied at Woodford County High School for Girls, then transferred to Ilford County High School for Boys to study mathematics and science, as her school did not offer these subjects.
She earned her BSc from Bedford College for Women in 1922, graduating in physics with an MSc from University College London in 1924.
Yardley came top in the University of London BSc examination, with the highest marks in 10 years. As a result, the Nobel physicist Prof William Bragg, one of her examiners and a pioneer of X-ray diffraction, invited her to join his research school at University College London.
After beginning her research career, in 1927 Yardley married Thomas Jackson Lonsdale. After her marriage, Lonsdale worked at the University of Leeds in the late 1920s, but after having three children, she cared for them nearly full time in the early 1930s.
In 1934, Lonsdale returned to work with Bragg at the Royal Institution as a researcher. Two years later, University College London awarded her a DSc.
Lonsdale had been brought up in the Baptist religion, but she and her husband became Quakers in 1935. Already committed pacifists, both were attracted to Quakerism for this reason.
Lonsdale served a month in Holloway prison during the Second World War because she refused to register for civil defence duties and pay a fine for refusing to register.
She was active in movements to promote peace, including the Pugwash Movement, the Atomic Scientists’ Association (of which she was a vice-president), and the Women’s International League for Peace and Freedom (president).
She also helped start the Young Scientist’s section of the British Association for the Advancement of Science.
In 1956, she was given the title Dame Commander of the Order of the British Empire.
Lonsdale also made important investigations into natural and synthetic diamonds and the mechanism of diamond synthesis, and in 1966, a rare form of hexagonal diamond was named lonsdaleitein in her honour.
In 1965, the Lonsdales moved to Bexhill-on-Sea when Thomas retired. Kathleen retired three years later.
She died on 1 April 1971, aged 68.
A decade later, the chemistry building at University College London was renamed the Kathleen Lonsdale Building in her honour.
In 1998, the new Aeronautical and Environmental Building at the University of Limerick was officially named the Kathleen Lonsdale Building.
NUI Maynooth instituted a Lonsdale scholarship to mark her connection with Kildare, and a commemorative plaque was erected at the former Yardley family home in Newbridge in 2003.
To vote for Lonsdale as Ireland’s Greatest Woman Inventor, click here.
Read about the other finalists in our Ireland’s Greatest Woman Inventor competition:
Women Invent Tomorrow is Silicon Republic’s year-long campaign to champion the role of women in science, technology, engineering and maths