Kathleen Lonsdale

Verified Timeline

Lore & Background

Kathleen Lonsdale was born Kathleen Yardley in Newbridge, County Kildare, Ireland, the youngest of ten children, four of whom died in infancy. Her father had issues with alcohol, and the family moved to Seven Kings, Essex, England in 1908 when she was five. She attended Downshall Elementary school from 1908 to 1914, then studied at Ilford County High School for Girls, transferring to Ilford County High School for Boys to study mathematics and science because the girls' school did not offer these subjects. In 1919 she began studying at Bedford College for Women, graduating in 1922 with the highest score in physics that any student at London University had ever achieved. She completed an MSc in physics from University College London in 1924, and William Henry Bragg offered her a research position. In 1924 she joined Bragg's crystallography research team at the Royal Institution. Following her marriage in 1927 to Thomas Jackson Lonsdale, she moved to the University of Leeds, where she set up X-ray equipment using a grant from the Royal Society and balanced her work on space groups with looking after her children. At Leeds, Professor Christopher Ingold suggested she investigate the crystal structures of hexamethylbenzene and hexachlorobenzene; in both cases she showed the molecules to have a planar, hexagonal structure, settling the long-standing dispute about the structure of benzene. She returned to work with Bragg at the Royal Institution in 1934, and was awarded a DSc from the University of London in 1936. In 1945 she was one of the first two women elected a Fellow of the Royal Society. She returned to University College London in 1946 as a reader, and in 1949 was appointed Professor of Chemistry and head of the Department of Crystallography, the first woman professor at UCL. As a keen table tennis player, she used ping pong balls to demonstrate molecular structures; one model of the silicate group Si2O5 is in the Science Museum collection. Lonsdale became a Quaker in 1935, simultaneously with her husband, and was a committed pacifist and Sponsor of the Peace Pledge Union. During the Second World War she served a month in Holloway prison because she refused to register for civil defence duties or to pay a fine for refusing to register. This experience led her to become a prison reform activist, and she joined the Howard League for Penal Reform. In 1953 she delivered the Swarthmore Lecture titled 'Removing the Causes of War'. She was appointed the first secretary of the Churches' Council of Healing by the Archbishop of Canterbury William Temple. Lonsdale died on 1 April 1971, aged 68, from an anaplastic cancer, possibly related to her exposure to X-rays.

Reader's Guide

Kathleen Lonsdale's significance rests on her foundational crystallography work and her pioneering role for women in science. Her 1929 proof that the benzene ring is flat, using X-ray diffraction on hexamethylbenzene, resolved a long-standing dispute in organic chemistry. Her 1931 use of Fourier spectral methods while solving hexachlorobenzene was a first in the field. She was one of the first two women elected a Fellow of the Royal Society in 1945, the first female professor at University College London, the first woman president of the International Union of Crystallography (1966), and the first woman president of the British Association for the Advancement of Science (1967). Her pacifism led to a month in Holloway prison during the Second World War, which turned her into a prison reform activist and member of the Howard League for Penal Reform. She was also the first secretary of the Churches' Council of Healing. Her legacy includes the carbon allotrope lonsdaleite named in her honor, buildings at University College London, the University of Limerick, Dublin City University, and Maynooth University, and a Royal Irish Academy chemistry prize named after her since 2000. A blue plaque was unveiled at her childhood home in Seven Kings, London on 1 April 2021.

Did You Know?

• She proved the benzene ring is flat in 1929 by using X-ray diffraction to elucidate the structure of hexamethylbenzene.
• She was the first to use Fourier spectral methods while solving the structure of hexachlorobenzene in 1931.
• She was one of the first two women elected a Fellow of the Royal Society in 1945, along with Marjory Stephenson.
• She served a month in Holloway prison during the Second World War for refusing to register for civil defence duties.
• The carbon allotrope lonsdaleite, a rare harder form of diamond found in meteorites, was named in her honor.