A lecture by Dr. Peter E. Childs
to mark the official opening of the Kathleen Lonsdale Building,
University of Limerick
20th. April 1998

Introduction
Kathleen Lonsdale (nee Yardley) was born on the 28th. January 1903 in Newbridge, Co. Kildare and died in England on the 1st. April 1971. Although her name is not well-known outside her own subject, she played a fundamental role in establishing the science of crystallography and in her scientific career scored several important 'firsts'. Her contemporary and friend Dorothy Hodgkin, Nobel Laureate in Chemistry 1964, said of her: "There is a sense in which she appeared to own the whole of crystallography in her time." In this lecture I want to review the main details of her life, then her scientific achievements, other non-scientific aspects of her life, and finally to assess her importance. Table 1 gives a brief chronology of her life.

Early life and education
Kathleen Yardley was the youngest of ten children, born to Harry and Jessie Yardley, in Newbridge, Co. Kildare. Her father was postmaster at Newbridge Post Office, following a career in the British army. He married Jessie Cameron, a Scot, in 1889. He read widely and Kathleen later said "I think it was from him that I inherited my passion for facts." Unfortunately he had a drink problem and the home wasn't happy, and in 1908 Kathleen's mother left him and brought the children to Seven Kings, Essex. He only visited them occasionally and died when Kathleen was 20. Her mother was a Christian of the Strict Baptist persuasion and Kathleen's earliest memories are attending Church of Ireland services and the Methodist Sunday School in Newbridge, and learning to count with yellow balls in the local school. She was the youngest of ten children, four girls and six boys. Four of her brothers died in infancy and Kathleen commented in later life: "Perhaps, for my sake, it was as well that there was no testimony against a high birth rate in those days."

From 1908-1914 she attended Downshall Elementary School, Seven Kings and won a County minor scholarship to the County High School for Girls in Ilford, where she went from 1914 to 1919. She was a good student and showed ability in Mathematics and the Sciences. She attended classes in Physics, Chemistry and Higher Mathematics at the High School for Boys (the only girl) as her school didn't offer these subjects. Her older siblings weren't allowed to stay on at school but had to go out to work to help support the family, as they were very poor. Her brother Fred Yardley became one of the earliest wireless operators and was the person who received the last signals from the Titanic in 1912.

Table 1 Chronology of Kathleen Lonsdale's Life

Kathleen was fortunate in being the youngest child and she stayed on at school and took the Cambridge Senior Examination and won a County Major Scholarship, with distinctions in six subjects. The local education authority wanted her to stay on and try for Cambridge (she was only 16) but she wanted to go to university as soon as possible. She went for an interview at Bedford College for Women, part of the University of London, and was allowed to enter despite her age. She started to read Mathematics, living at home, and after winning a university scholarship at the end of the first year, switched to Physics. Her old headmistress advised against this as she said she would never distinguish herself in Physics. However, Kathleen came top in the University of London honours B.Sc. examination in 1922, with the highest marks in ten years, and she was invited by Professor W.H. Bragg, one of her examiners and one of the pioneers of X-ray diffraction, to join his research school at University College, on a research grant of £180 a year. W.H. Bragg was an inspiring supervisor and Kathleen wrote of him: "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." She chose to work on solving the structure of simple organic crystals, on Bragg's advice, and also started to collaborate with another research student, W.T. Astbury, on the theoretical basis of X-ray diffraction from crystals. In 1923 W.H. Bragg moved to the Royal Institution in London and Kathleen went with him. There Bragg set up an international team of young researchers, including John Desmond Bernal (born in Nenagh), and others who later achieved international recognition. Kathleen was the only woman at first, as at that time there were very few women scientists. However, W.H. Bragg was quick to take on women to do research and consequently he has many 'female X-ray descendants'.

She met Thomas Lonsdale, also a research student at University College, but in engineering, and they were married in 1927. They moved to Leeds in 1927 where Thomas got a job in the Silk Research Association, based at the University of Leeds. Thomas encouraged her to continue her scientific work and she continued some successful work on X-ray diffraction in the Department of Physics. Professor C.K. Ingold in the Chemistry Department gave her some beautiful crystals of hexamethylbenzene to work on and this was the first structure she solved correctly. It showed conclusively that the benzene ring was flat, something that chemists had been arguing about for 60 years, and this was an important milestone in organic chemistry. She also applied Fourier analysis for the first time to analyse X-ray patterns in solving the structure of hexachlorobenzene.

In the evenings Thomas did experiments in the kitchen for his Ph.D. and Kathleen did her calculations (by hand using logarithim tables!). In 1929 her first child Jane was born and soon afterwards they returned to London, living first at Windsor and then at Harmondsworth. A second daughter, Nancy, was born in 1931 and a third child, Stephen, was born in 1934.

This move disrupted her experimental work again and she spent her time doing calculations at home, working out the structure factor formulae for all the space groups. In 1931 Sir William Bragg wrote to her: "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?" In fact she needed more than £200 and Bragg managed to get £300, which enabled her to move back into research at the Royal Institution with him where she stayed for the next 15 years, existing on short term grants and fellowships. For a time she occupied Michael Faraday's old room. W.H. Bragg died in 1942 but Kathleen stayed on to work with his successor Sir Henry Dale. She was awarded the D.Sc. by University College in 1936 for her work on the structure of ethane derivatives.

After the war she was encouraged to move into academic life and in 1946 she became Reader in Crystallography at University College, London. In 1949 she became Professor of Chemistry and Head of the Department of Crystallography. Only then, at the age of 43, did she start to build up her own research school and get involved in teaching undergraduates and postgraduates.

From 1943 to the end of her life she travelled around the world lecturing and visiting scientific colleagues. Her first trip abroad was in 1943 when Kathleen visited the Dublin Institute of Advanced Studies to lecture in the Summer School, chaired by Erwin Schrodinger and attended by the Taoiseach, Eamon de Valera. At that time she was in mid-career and already had an established reputation.

In her time at the Royal Institution she worked in many areas related to X-ray crystallography, theoretical and experimental. In 1945 Kathleen Lonsdale and Marjory Stevenson, a microbiologist, were elected as the first women Fellows of the Royal Society, after the rules were changed to allow women to be Fellows! This a singular honour and mark of their scientific achievement in a man's world.
In 1965, when Thomas retired, the Lonsdales moved to Bexhill-on-Sea, which meant 5 hours travelling each day to and from University College. Her husband had retired on his 60th Birthday and from then on he helped her with her voluminous correspondence. She retired in 1968 and became an Emeritus Professor at UCL, but she carried on working and publishing to the end of her life. She was ill for some time with cancer and in December 1970 she entered hospital. She was allowed out briefly for special occasions, and carried working on papers and a book from her sick-bed. Shortly after celebrating Thomas' 70th birthday she died from cancer, on April 1st 1971.

In 1981 the chemistry building at University College, London was renamed the Kathleen Lonsdale Building in her honour and in 1998 the new Aeronautical and Environmental Building at the University of Limerick was officially named the Kathleen Lonsdale Building, marking her Irish birth (see Figure 1).

Figure 1: The Kathleen Lonsdale Building at UL

Scientific achievements
Her published papers stretch from the first in 1924 (on 'The crystalline structure of succinic acid, succinic anhydride and succinimide', Proc. R.Soc.Lond.A 105, 451) to the last one, published posthumously in 1972 (an English version of a paper, with D.J. Sutor, on 'Crystallographic studies of urinary and biliary calculi', Soviet Phys. Crystallogr., 16 (6), 1972, 1060). They are listed at the end of Dorothy Hodgkin's biographical memoir and cover many aspects of crystallography and related topics: mathematical crystallography; structures of organic molecules; magnetic anisotropy in crystals and molecules, particularly aromatic compounds; diffuse scattering and thermal vibrations in crystals; study of synthetic diamonds; solid state reactions; methonium compounds; structure and composition of bladder stones and other calculi.

Although crystallography goes back to the work of Hauy (1743-1822) it didn't really take off until 1912 when Max von Laue showed that the newly-discovered X-rays (1895) could be used to look inside crystals. William and Lawrence Bragg, father and son, then applied the technique to solve simple inorganic structures and developed Bragg's Law to explain X-ray scattering from atomic planes in crystals. World War I disrupted research but "after the war, the Braggs divided the crystal world between them. The father, at University College, London, chose the organic structures and quartz, and his son, at the University of Manchester, took the rest of the inorganic substances." (Julian, 1990, p.341).

Kathleen Lonsdale was to work in the area of X-ray crystallography from 1922, when she started as a young research student, to her death in 1971. She produced a steady stream of papers during that time, trained many students in the techniques and made contributions in many areas. Amongst the significant scientific contributions she made were as follows:

She established the long-disputed structure of benzene and showed that it was planar and symmetrical. Professor C.K. Ingold said of this seminal paper: "Ever so many thanks for your wonderful paper on hexachlorobenzene .. The calculations must have been dreadful but one paper like this brings more certainty into organic chemistry than generations of activity by us professionals."

· She was the first to apply Fourier methods to solving organic structures

· She showed that sigma and pi electrons existed in benzene and provided experimental evidence for molecular orbital theory.

· She helped to establish the theoretical basis of structure analysis by drawing up structure factor tables (with W.T. Astbury) and then editing the prestigious International Tables of X-Ray Crystallography, the crystallographer's bible.

· She made important investigations into natural and synthetic diamonds and the mechanism of diamond synthesis. In 1966 a rare form of hexagonal diamond was named lonsdaleite in her honour. She replied in a letter to Clifford Frondel of Harvard, who had suggested the name: "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 it is generally rather mixed up!" (Julian, p. 356)

· She did important work on thermal motion and diffuse scattering in crystals.

· In 1962 she took up the study of kidney stones and other calculi, and loved to show an X-ray photo of Napoleon III's bladder stone (Lonsdale, 1968).

Other interests
Kathleen Lonsdale was brought up as a Strict Baptist by her mother but as an adult she found its beliefs rather restrictive. She and her husband, having looked around for a suitable church to join, eventually joined the Quakers, or Society of Friends. Their strongly pacifist yet activist position appealed to Kathleen, whose abhorrence of war had grown since WWI when she lived near London under the Zeppelin flight path. At the beginning of WWII everyone was expected to register for war service of some sort, but Kathleen ignored the requests as she did not feel able to contribute in any way to the war effort. She was eventually summonsed and fined £2. When she refused to pay the fine she was sent to Holloway Prison for one month. While in prison she wore prison uniform and had to clean floors and do other jobs. However, she was allowed books and papers ands managed to get seven hours scientific work done each day! This marked the start of a life-long interest in prison reform and she became a Prison Visitor for several women's prisons after the war. She visited many countries after the war including Russia and China, but she had trouble getting a visa to visit the USA. One embassy official told her: "You've been to the three most difficult places' Russia, China and gaol."

She was also involved in movements to promote peace and supported the foundation of the Pugwash Movement, and served as Vice-President of the Atomic Scientist's Association and President of of the Women's International League for Peace and freedom. She was often invited to speak on non-scientific topics at home and abroad, including science and religion, and the role of women in science. She was a great advocate for the increased participation of women in science, and knew first-hand the difficulties of combining marriage and a family with a professional career. She once wrote: "Sir Lawrence Bragg once described the life of a university professor as similar to that of a queen bee, nurtured, tended and cared for because she has only in function in life. Nothing could be farther from the life of the average professional woman." She had very strong views on the need to encourage and support women who wanted to have a family and use their scientific talents, and she had this to say about it in 1970:

"Any country that wants to make full use of all its potential scientists and technologists could do so, but it must not expect to get the women quite so simply as it gets the men. Its seems to me that marriage and motherhood are at least as socially important as military service. Government regulations are framed that a man returning from military service is not penalised by his absence. Is it Utopian, then, to suggest that any country that really wants married women to return to a scientific career, when her children no longer need her physical presence, should make special arrangements to encourage her to do so?"

She was very keen on encouraging science education and she helped the start the Young Scientist's section of the British Association. She made a note to herself: "Never refuse an opportunity to speak in schools".

Some firsts
Kathleen Lonsdale was one of the women pioneers in a man's world, the world of professional scientists. She opened the way for other women and crystallography became an area of the physical sciences where women became prominent. When she started research in 1922 X-ray crystallography was only a decade old and the Braggs, father and son, were the leading exponents in the world. Maureen Julian showed in a survey of crystallographers that around 14% were women in the early 1990s, compared to around 2% of physicists. Thus women are more numerous and more prominent in this area of science than in related sciences. This was due firstly to the influences of William and Lawrence Bragg, who encouraged many women to take up crystallography, and then to the influence of Kathleen Lonsdale, who was one of the most prominent women in science from the late 1930s to her death in 1971. Dorothy Hodgkin, although not a student of Kathleen Lonsdale, was influenced by reading one of her papers while an undergraduate. Dorothy Hodgkin went on to win a Nobel Prize in Chemistry for her application of crystallography to solving the structures of important biological molecules, and she also encouraged many women to take up crystallography as a career. But Kathleen Lonsdale was the pioneer woman in this area and so she achieved many firsts, the most notable being:

· One of the first two women elected as Fellows of the Royal Society (1945)
· First woman professor at University College, London (1949)
· First woman president of the International Union of Crystallography (1966)
· First woman president of the British Association of Science (1968)

Some comments on Kathleen Lonsdale
"Kathleen Lonsdale had a profound influence on the development of X-ray crystallography and related fields in chemistry and physics. Very few have made so many important advances in so many different directions."

J.M.Robertson Dictionary of Scientific Biography

"Her experimental determination of the structure of the benzene ring by X-ray diffraction, which showed that all the ring C-C bonds were of the same length and all the internal C-C-C angles were 120 degrees, had an enormous impact on organic chemistry."

K.N. Trueblood, UCLA

W.H. and W.L Bragg and J. D. Bernal "were enlightened enough to think that women could do good science. There were young women like Dorothy Hodgkin and Kathleen Lonsdale who were invited to work with them. They showed a flair, they did the work brilliantly and seemingly had the capacity to deal with symmetry, patterns and numbers. I guess that's really where it started. Once you get a tradition of women established in a subject, you get more. I hate the phrase 'role model', but it does seem to have some effect."

(Professor Judith Howard, University of Durham)

She was "..the first woman crystallographer to attain a world-wide reputation not only as a scientist but as a humanist as well. Her willingness to be of service to others was exemplified in her careful work on the International X-ray Tables as well as in her prison reform and peace efforts. Her scientific achievements were many. …Kathleen Lonsdale was indeed an incredible worker, a methodical organiser, and a scientist of highest order."

Maureen M. Julian (p.359)

Conclusion
I hope that this paper has given you enough information to assess the importance of Kathleen Lonsdale's life and work. She was a remarkable person and a world-class scientist. She started off in Mathematics, moved to Physics and ended up as Professor of Chemistry, although she herself said that she knew very little chemistry, and no organic chemistry. She was encouraged to come into the developing field of X-ray crystallography by W.H. Bragg, who with his son W.L. Bragg, did much to remove the barriers to women entering the physical sciences in the 1920s and 30s. But Kathleen Lonsdale made the most of this opportunity and her abilities, despite an unfavourable family background and the heavy demands of family life and several moves. She said in her characteristically humble way: "My own research life has been greatly enriched by having been broken into by periods of enforced change. I was not idle while I had my three children; far from it. But it gave me the opportunity of standing back, as it were, and looking at my work. And I came back with new ideas." (Quoted by Hodgkin, p. 473)

She achieved many firsts in the arena of professional science and broke through several glass ceilings, blazing a trail that many women have followed, particularly in the field of crystallography where women now have one of the highest representations compared to other physical sciences.

In many ways her work for peace and for prison reform, in the best traditions of Christian activism, were as significant as her scientific work. The title of one of her non-scientific books was Is Peace Possible? and another was The Christian Life Lived Experimentally. She was an activist in the best sense of the word, and she implemented this in her scientific as well as in her Christian and social activities. In one of her talks on religion she said: "It is necessary to believe that in God's world there is always a right course of immediate action." (Hodgkin, p. 472) That was a philosophy that she put into action herself and persuaded others around her to do the same. Kathleen Lonsdale is someone we can look up to not only as a great scientist who achieved much, despite many difficulties, but also as a good human being.

References
Hodgkin, D.M., Kathleen Lonsdale, Biographical Memoirs of the Fellows of the Royal Society, 41, 447-448 (1975)

Julian, M.M. 'Women in Crystallography' in Women of Science (Bloomington: Indiana University Press, 1990) 335-383

Laidler, K.J., 'Kathleen Lonsdale (1903-1971)', Chem13News, #255, 1-5 (1997)

Lonsdale, K, 'Human Stones', Scientific American, 219 (1968) 104-111

Robertson, J.M.,'Kathleen Lonsdale' in Dictionary of Scientific Biography, III, (New York, Scribners: 1973) 484-486

Howard, J, interview with Martyn Kelly (URL: http://www.dur.ac.uk/~dde0www/dl.2/howard.htm)

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