Kathleen Lonsdale (1903-1971) was an early pioneer of X-ray crystallography, a field primarily concerned with studying the shapes of organic and inorganic molecules.
In 1929, Kathleen Lonsdale was the first to prove experimentally that the hexamethylbenzene crystal, an unusual form of the aromatic compound, was both hexagonal and flat in shape. In 1931, she was the first to use Fourier analysis to illustrate the structure of hexachlorobenzene, an even more difficult organic structure to analyze.
In 1945, Lonsdale was the first woman, along with microbiologist Marjory Stephenson, admitted as a fellow to the Royal Society. She was the first female professor at University College, London, the first woman named president of the International Union of Crystallography, and the first woman to hold the post of president of the British Association for the Advancement of Science. She accepted her achievements as a pioneering woman scientist with characteristic humility. In 1966, the "lonsdaleite, " a rare form of meteoric diamond, was named for her. According to the Journal of Chemical Education, upon learning that Clifford Frondel at Harvard University had suggested the name, she wrote to him: "It makes me feel both proud and rather humble that it shall be called lonsdaleite. Certainly the name seems appropriate since the mineral only occurs in very small quantities (perhaps rare would be too flattering) and is generally rather mixed up!"
Lonsdale was born January 28, 1903 in Newbridge, Ireland, a small town south of Dublin. She was the youngest of ten children born to Jessie Cameron Yardley and Harry Frederick Yardley, who was postmaster for the British garrison stationed there. Her father was a heavy drinker, and in 1908, when Kathleen was five years old, her parents were separated. Her mother moved the family moved to Seven Kings, England, a small town east of London. Growing up in England, Kathleen won a scholarship to attend County High School for Girls in Ilford. At the age of 16, she enrolled in Bedford College for Women in London, where in 1922 she received a B.S. in mathematics and physics. She graduated at the head of her class, receiving the highest marks in ten years, and among her oral examiners was William Henry Bragg, the 1915 Nobel Laureate in Physics. He was so impressed with her academic performance that he invited her to work with him and a team of scientists using X-ray technology to explore the crystal structure of organic compounds.
Lonsdale worked with Bragg from 1922 to 1927, first at University College, London, and then at the Royal Institution. During these years she also completed her research for a master's thesis on the structure of succinic acid and related compounds; she published it in 1924, with collaborator William Thomas Astbury, as a theory of space groups that included tables for 230 such groups and mathematical descriptions of crystal symmetries.
On August 27, 1927, she married Thomas Lonsdale, who was a fellow student of hers. They moved from London to Leeds, where her husband worked for the British Silk Research Association by day and completed his doctoral dissertation on the torsional strengths of metals by night. Lonsdale worked at the University of Leeds, studying the structure of hexamethylbenzene, and in 1929 she produced the first proof of its hexagonal, planar shape. Her discovery was made independently of her colleagues' work in London, and it was supported by Bragg even though it contradicted his own theory that the compound had a "puckered" shape.
In 1930, the Lonsdales returned to London, where her husband had found a permanent post at the Testing Station of the Experimental Roads Department in the Ministry of Transport at Harmondsworth. Between 1929 and 1934, Lonsdale gave birth to their three children; she worked at home during this period, developing formulae for the structure factor tables. These formulas were published in 1936 as "Simplified Structure Factor and Electron Density Formulae for the 230 Space-Groups of Mathematical Crystallography." For the study of ethane derivatives contained in this book, Lonsdale received her doctorate of science.
In 1934, Lonsdale returned to the Royal Institution, where she would work with Bragg until his death in 1942. Upon her return, however, she found that no X-ray equipment was available. Forced to make do with a large electromagnet, Lonsdale undertook experimental work that eventually proved the difference between sigma and pi electronic orbitals, thus establishing the existence of molecular orbitals. She then turned her attentions to the field of thermal vibrations, finding that divergent X-ray beams could be used to measure the distance between carbon atoms.
Lonsdale was made a fellow of the Royal Society in 1945, and in 1946 she founded her own crystallography department at University College, London. In 1949, Lonsdale was named professor of chemistry at the college, her first permanent academic post following years of living from one grant to the next. During these years, she wrote a popular textbook, Crystals and X-Rays (1948), and served as editor-in-chief of the first three volumes of the International X-Ray Tables (1952, 1959, and 1962). In 1949, Lonsdale began working with South African scientist Judith Grenville-Wells (later Milledge), eventually collaborating with her on a study of diamonds, as well as on studies of minerals at high temperatures and high pressures, and how solid state reactions work. Milledge later became executor of Lonsdale's literary estate. In the 1960s, Lonsdale became fascinated with body stones (in lectures, she was fond of exhibiting an X ray of a bladder stone from Napoleon III), and she undertook extensive chemical and demographic studies of the subject. She retired from University College in 1968.
Lonsdale and her husband were committed pacifists. They became Quakers in 1936 and together worked toward world peace, as well as prison reform. During World War II, she and her husband gave shelter to refugees, and in 1943 Lonsdale spent a month in jail for refusing to register for war duties and then refusing to pay a fine of two pounds. In 1956, she wrote a book in reaction to extensive nuclear testing by the United States, the Soviet Union, and Great Britain. Entitled Is Peace Possible?, the book explored the relationship between world peace and world population needs, as viewed through her own experience as the youngest of ten children. Lonsdale was against nuclear weapons of any kind, and she worked tirelessly for world peace.
In 1956, just a day after the first of her ten grandchildren was born, Lonsdale was named a Dame Commander of the Order of the British Empire, and in 1957 she received the Davy Medal of the Royal Society. In 1966, she became the first female president of the International Union of Crystallography, and in 1968 the first woman to hold the post of president of the British Association for the Advancement of Science. Following her husband's retirement from the Ministry of Transport, the Lonsdales moved to Bexhill-on-Sea. On April 1, 1971, she died of cancer in London.
Further Reading on Kathleen Lonsdale
Biographical Memoirs of Fellows of the Royal Society, Volume 21, Royal Society (London), 1975, pp. 447-489.
Kass-Simon, G. and P. Farnes, editors, Women of Science, Indiana University Press, 1990, pp. 355-359.
Julian, Maureen M., "Profiles in Chemistry: Dame Kathleen Lonsdale (1903-1971), " in Journal of Chemical Education, Volume 59, November, 1982, pp. 965-966.
Mason, Joan, "The Admission of the First Women to the Royal Society of London, " in Notes and Records of the Royal Society of London, Volume 46, 1992, pp. 279-300.