Researcher in the DFRL, 1923–1927, 1930–1946
Kathleen Yardley was born in Newbridge, Ireland, but the family later moved to Essex where she was brought up in somewhat restricted circumstances. She studied mathematics and physics at Bedford College, London, where she reportedly secured top place in London University’s BSc examination. William Henry Bragg was one of her examiners and was so impressed with her that he offered her a post in his research team working on the crystal structure of organic compounds first at University College, London, and then at the Royal Institution. Her major work was on the theory of space groups to help determine where possibilities of molecular symmetry might occur and demonstrating for the first time that the benzene ring was hexagonal and planar and calculating its precise dimensions.
In 1927 she married Thomas Lonsdale and moved to Leeds for three years before she returned to the Royal Institution where she effectively led research there following Bragg’s death in 1942. In 1946 she was appointed Reader in Crystallography at University College and Professor of Chemistry there in 1949.
She was the first woman Fellow of the Royal Society of London in 1945, winning the Davy medal of the society in 1957; she was also the first woman President of the British Association in 1968. Despite a very active scientific career she was involved, as a Quaker by convincement, in both the peace movement and in prison reform, having served a month in Holloway prison in 1943 for refusing to register for civil defence duties.