Kathleen Lonsdale (1903-1971)

Dame Kathleen Lonsdale was a crystallographer, famous for her role as a female scientist and as a pioneer in using X-rays to study crystals. Lonsdale (then Yardley) was born in County Kildare, Ireland, the youngest of ten children. Concerned about stability in the country, her underprivileged family moved to England when she was five years old. During her education she was the only girl to study mathematics and science at the local boys’ school, since her own school for girls did not offer these subjects.

She began a degree in mathematics at Bedford College for Women, but converted to physics after the first year. In 1922 she finished top of her class, and after completing a master’s degree in physics in 1924 at University College London, she was offered a place in Sir William Henry Bragg’s crystallography research team at the Royal Institution. Unusually for the time, and encouraged by her husband, she returned to work in 1934 after having their three children.

Lonsdale’s greatest scientific contribution was her discovery of the molecular structure of benzene in 1929 and hexachlorobenzene in 1931, determining that the former, a crucial compound in organic chemistry, is a flat regular hexagon using the method of X-ray diffraction. She also studied the synthesis of diamonds.

Both pacifists, Lonsdale and her husband converted to Quakerism in 1935. She spent a month during the Second World War in prison for refusing civil defence duties, where she was permitted to receive scientific papers and apparatus on which to work in her spare time. She continued to remain a dedicated Christian campaigner for prison reform as well as global peace.

In 1945, Lonsdale was one of the first two women to be admitted as Fellows of the Royal Society, and in 1949 became the first female professor at University College London when she was made head of the Department of Crystallography. She remained there until her retirement in 1968.

Lonsdale was made a dame, received the Davy Medal for chemistry in 1957, and in 1966 became the first female president of the International Union of Crystallography, as well as of the British Association for the Advancement of Science the following year. She also encouraged young people to take up the study of science.