The Queen of Crystallography
Through scholarships, Kathleen Lonsdale escaped poverty to make science history.
1927 was a banner year for Kathleen Yardley. She married her college sweetheart, engineering student Thomas Lonsdale, moved from London to Leeds, and secured a part-time demonstrator and researcher position in the physics department at the University of Leeds. Though she had been researching crystals since graduating five years prior, it was here that she undertook the work that would make her famous.
A chemistry professor at Leeds presented her with the beautiful puzzle of hexamethylbenzene crystals. By using X-ray diffraction, she proved that the benzene ring is a flat molecule. Her findings were published in the April 6, 1929 Proceedings of the Royal Society. Kathleen had settled, once and for all, a dispute that had fiercely divided the scientific community for 60 years. Next, she became the first person to use Fourier spectral methods to solve the structure of hexachlorobenzene. These results were published in October 1931.
This work is impressive enough on its own. But when you also take into consideration the environment in which it was produced, well then it’s truly unbelievable. Kathleen completed most of her calculations by hand at home, deriving the structure factor formulae for all space groups. She was even calculating during childbirth and while caring for children. Yes, the Lonsdale’s first child, Jane, was born in 1929, the same year as that groundbreaking publication.
Kathleen said she “found it rather difficult to do everything in the home” AND find time for work after having a baby. Money was already tight before the baby came along since her job was only part-time and her husband was hard at work on his PhD.
Lucky for her—and for science—she had friends in high places who helped ensure that her professional aspirations and brilliant mind were not swallowed by domesticity. She wrote to her former supervisor, physicist and chemist William Bragg, explaining her struggles. He persuaded the managers of the Royal Institution to give her a grant of £50 so she could hire household help.
“Her name was Mrs. Snowball (it really was!),” Kathleen chirped. “And with her to wash and clean, I managed to care for the baby, cook and continue the structure analysis of C6Cl6.” (hexachlorobenzene)
The following year, the family moved back to London and Kathleen stayed at home, working when she could. Their second child, Nancy, was born in 1931. That November, William excitedly wrote Kathleen with “A piece of good news! Sir Robert Mond is giving me £200 with which you are to get assistance at home to enable you to come and work here. Can you come and see me soon?”
Kathleen responded with yet more calculations, this time in relation to exactly how much it would cost to pay for the household help required to replace her. “I did some hasty sums and produced an ‘Estimated Annual Budget’ which convinced me (and him) that £200 was not enough.” She needed at least £277.
“I think he got me £300,” she later remembered. With childcare and living costs covered, she was able to return to work with William at the Royal Institution in London in 1932, where she stayed for the next fifteen years (barring a short stint away for the birth of their third child, Stephen, in 1934. Kathleen occupied Michael Faraday’s old room. Her income slowly rose to £400 a year. She had always relied on institutional funding to make her educational and professional dreams a reality.
Kathleen Yardley was born in Newbridge, County Kildare, Ireland, on January 28, 1903. She was Harry Yardley and Jessie Cameron’s tenth and final child. Of their four girls and six boys, four of the boys died in infancy. Harry was curious and well-read; Jessie was adept with languages. The family was quite poor, and Harry’s drinking made matters worse. Soon the marital quarreling became too much, as did the increasing violence in Ireland, and Jessie took the children and moved to Seven Kings, Essex, England, when Kathleen was five years old.
In 1914, she won a scholarship to attend Ilford County High School for Girls. Her oldest brother, Fred, had also been awarded one, but was unable to use it since he had to help support the family. He was one of the very first wireless operators, and had received the last signals from the Titanic in 1912. Kathleen was the only girl in her school who attended classes in physics, chemistry, and higher mathematics at the boys’ high school. The girls’ school didn’t offer these subjects.
Kathleen earned distinctions on her English, French, history, geography, botany, and mathematics senior exams. She also won the Royal Geographical Society’s medal for the highest marks on her geography papers. The local education authority offered to increase Kathleen’s scholarship if she would stay at school and try to get into Cambridge University, but she was anxious to attend university as soon as possible. She interviewed with the mathematics professor at University College London’s Bedford College for Women; her mother cried tears of joy when he said Kathleen could attend at age sixteen.
By the end of her first year of college, Kathleen had switched her major from mathematics to physics. She was worried the only career option with a math degree was teaching. She has also been seduced by the exciting experimental nature of physics. Kathleen may have also been swayed by her affection for the people in the physics department: “I rather suspect that my relationship with some of the students taking physics and my affection for some of the physics staff may have had a stronger influence on my decision than I would have admitted,” she later wrote.
In 1922, Kathleen earned the highest grade of any student for the past 10 years on her bachelor of science exam. Jobs were scarce in the field; she remembered a fellow student applying for 150 positions before obtaining a job. But Kathleen’s incredible exam scores saw her invited by William Bragg, one of her examiners and an X-ray diffraction trailblazer, to join his research team at the university. He tempted her with a grant of £180 a year and the opportunity to work toward her master’s degree.
“It was luxury and I jumped at it,” Kathleen declared. She lived with her parents and contributed substantially to the family expenses.
It would take three months to collect everything she would need to properly study crystal structures (an ionization spectrometer and a gold leaf electroscope), William explained, and she should put it all together by herself. Before long, she was examining the structure of simple organic crystals and collaborating with X-ray specialists. William was a tremendous team leader: “He inspired me with his own love of pure science and with his enthusiastic spirit of enquiry and at the same time left me entirely free to follow my own line of research.” When William moved to the Royal Institution in London, Kathleen, and many others on the team, went with him.
The study of crystals dates back to the early 1800s, but it wasn’t until 1912, when the new technology of X-rays was used to look inside crystals, that crystallography could become a fully realized discipline. The father-son team William and Lawrence Bragg began to map simple inorganic structures, then created Bragg’s Law to explain X-ray scattering crystals.
Over the next two decades, Kathleen went on to earn a doctorate of science, become one of the first women Fellows of the Royal Society, was made Dame Commander of the Order of the British Empire, and was elected the first woman president of both the International Union of Crystallography and the British Association for the Advancement of Science. Her research spanned theoretical and experimental X-ray crystallography, including the synthesis of diamonds.
“There is a sense in which she appeared to own the whole of crystallography in her time,” 1964 chemistry Nobel laureate Dorothy Hodgkin asserted of her friend Kathleen.
Lifelong pacifists, Kathleen and her husband had converted to Quakerism back in 1935. During World War II, Kathleen refused to register for civil defense duties or pay the fine for refusing to register, so served a month in Holloway prison. The experience transformed Kathleen into an outspoken prison-reform activist.
After the war, Kathleen became professor of chemistry and head of the department of crystallography at her alma mater. She was the first tenured woman professor at that college, a position she held until 1968. Kathleen died of cancer on April 1, 1971, at age 68. Buildings named in her honor can be found at University College London, the University of Limerick, and Dublin City University. Lonsdaleite, a rare, harder form of diamond discovered in meteorites, is also named after her.
“The Royal Society’s first woman physicist,” by Melinda Baldwin. Physics Today, January 25, 2018.
“Woman of substance,” December 31, 2002. Chemistry World.
“Kathleen Lonsdale,” by Dorothy M. Hodgkin, Biographical Memoirs of the Fellows of the Royal Society, 1975.
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Olivia Campbell is a journalist and author specializing in women, history, and science. Her first book: Women in White Coats: How the First Women Doctors Changed the World of Medicine, was published March 2021 by HarperCollins/Park Row Books.
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