Kathleen Lonsdale: Master of Crystallography

In recent years, there has been a wonderful explosion of interest in the often-neglected historical women of science, and more information is available than ever before about the lives and achievements of these women.  Nevertheless, there are still some truly accomplished women of science who have not received as much attention as they deserve. This post is a small attempt to rectify this in the case of Kathleen Lonsdale (1903-1971), an Irish crystallographer who made fundamental contributions in her field and had influence far beyond, including socially and politically.

Kathleen Lonsdale, in 1968, via Wikipedia.

Kathleen Lonsdale, in 1968, via Wikipedia.

Kathleen Yardley* was born in 1903 in Southern Ireland, the youngest of ten children in a fundamentalist religious family. Growing concerned with Irish political unrest, Kathleen’s family relocated in 1908 to Seven Kings, Essex in England.

She showed great intellectual promise from an early age [1], and quite frankly never stopped showing it.  The girls’ school she attended from 1914-1919 did not offer classes in physics, chemistry and higher math, so she took them from the local boys’ school, and was the only young woman to do so.  When she took the Cambridge Senior local examination, she demonstrated high distinctions in English, French, history, geography, botany, and mathematics.  She was awarded a scholarship on this basis to continue her primary school education, but she was anxious to enter college as soon as possible.  At the age of 16, she earned admission to the Bedford College for Women in London, where she began a degree in mathematics.

After the first year, however, she opted to switch to physics, though she met with little support from the university or her old headmistress, none of whom felt that she could distinguish herself in the field.  Kathleen, on the other hand, felt particularly drawn to experimental work and dreaded the thought of becoming a teacher, which seemed her only career prospect with a math degree. She quickly began to prove her critics wrong, however, by heading the University list in the 1922 honors B.Sc. examination.

One of her examiners was William Henry Bragg, who in 1915 had won the Nobel Prize in Physics with his son Lawrence “for their services in the analysis of crystal structure by means of X-rays.” The Braggs had essentially created the field of X-ray crystallography, in which the atomic and molecular structure of crystalline materials can be deduced by analyzing how X-rays are scattered by them.  Bragg immediately offered Yardley an extremely generous position on his research team at University College London.

This is perhaps a good place to say a few words about X-ray crystallography.  X-rays and visible light are both electromagnetic waves, and when waves of a particular type combine, they can produce interference patterns of bright and dark spots.  The wavelength of visible light, however, is around 500 nanometers (billionths of a meter), whereas the spacing of atoms in a crystal is on the order of a few tenths of a nanometer.  Visible light is therefore totally insensitive to the fine structure of matter — in a sense, it cannot “see” this structure.  X-rays, however, have wavelengths as small as 0.01 nanometers, and such X-rays are very sensitive to atomic structure.  When a beam of visible light is shined on a smooth flat surface, it reflects; when a beam of X-rays is projected onto a smooth flat surface, it scatters into a pattern of bright dots.

An X-ray diffraction pattern of an enzyme, via Wikipedia.  The dark spots are the points where the X-rays developed the film.

An X-ray diffraction pattern of an enzyme, via Wikipedia. The dark spots are the points where the X-rays developed the film.

The position and brightness of these spots depends upon the crystalline structure of the material being probed, albeit in a complicated manner.  X-ray crystallography is the process of measuring the pattern of X-rays that scatter from a material and using that pattern to deduce atomic structure.

William Bragg was an incredibly supportive supervisor for Kathleen, and left her free to choose her own research project and to build the measurement apparatus herself from scratch.  She was more than up to the challenge and, at the suggestion of another research student, soon completed her first crystallographic project, the measurement of the structure of succinic acid.  When Bragg left the University College for the Royal Institution, Kathleen joined his group there, though she earned her M.Sc. from University College in 1924.

Kathleen Yardley with her fellow students, via her Biographical Memoir.

Kathleen Yardley with her fellow students at the Royal Institution, via her Biographical Memoir [1].

 In 1927, Kathleen Yardley married Thomas Lonsdale, who she had met years earlier at University College, and the couple moved to Leeds to follow Thomas’ work.  Fortunately, Kathleen found a wonderful partner who actively encouraged her research.  When she offered to give up her work to focus on housework, Thomas apparently told her [1] that he had “not married to get a free housekeeper.”

The move to Leeds did not slow down Kathleen at all; she was welcomed into the physics department at Leeds and received a grant to build her own experimental apparatus, which she did on her own, again.  With this equipment she made her first major discovery: she used crystallography to analyze the structure of hexamethylbenzene and confirm that a ring of benzene is flat and hexagonal.

Illustration of the historic benzene molecule, as first proposed by Kekulé.

Illustration of the historic benzene molecule, as first proposed by Kekulé, via Wikipedia.

From this discovery, Kathleen would go on to many, many other discoveries.  A few of them, as listed in [1]:

  • The structure of various aromatic compounds, like hexamethylbenzene.  As already noted, Lonsdale worked tirelessly on experimental crystallography.
  • Mathematical crystallography.  Lonsdale was an extremely talented mathematician, and could easily do many of the complicated calculations required in crystallography.  She worked extensively on the relation of so-called space groups to the observed X-ray scattering and tabulated these relationships, making it easier for others to solve for crystal structures.
  • Magnetic anisotropy of crystals and molecules.  When Kathleen returned to work after giving birth to her third child in 1934, no X-ray apparatus was available for her to work on.  There was, however, a large electromagnet present, and so she turned to measuring the magnetic response of crystals.
  • Thermal effects in crystals.  While working on an X-ray and magnetic experiment in the late 1930s with another researcher, Kathleen noted that some of the X-rays scattered formed diffuse smears, rather than distinct peaks.  She began an investigation into these diffuse smears and confirmed that they agreed with theoretical work suggesting they were the result of thermal vibrations of atoms and molecules.
  • Solid state reactions.  When a research student came to Kathleen with some peroxide-based crystals to analyze, they found that the X-ray images had diffuse streaks that increased with time.  They were indirectly observing a prolonged change in the chemical structure of the crystal, which Kathleen found fascinating, in large part due to its complexity.
  • Studies on bladder stones.  In 1962, Kathleen was approached by a medical doctor who wanted advice on how to analyze the structure of bladder stones that he had collected from around the world and determine how they had formed (and how to prevent them).  Later in life, Kathleen became interested in pursuing research that provided a societal benefit, and she jumped into the analysis, having studied over a thousand stones by 1969.

These are just a small number of Lonsdale’s scientific accomplishments.  She did not shy away from, and in fact she sought, quite difficult problems to work on; some of them are so difficult that it is hard to describe them in simple terms in a short paragraph!  I actually suspect that this is part of the reason that Lonsdale is not as well-known as other women scientists: it is simply hard to tell people what she did.  Her impact in the scientific literature in undeniable, however: without counting, she looks to have at least 200 published research papers.  William Bragg is not even the only Nobel Prize winner she collaborated with; she has several publications with Max Born.  Another collaboration, with the Indian scientist K.S. Krishnan, led to Lonsdale to become a vegetarian and later a vegan.

Though she worked almost tirelessly on science (more on this later), it was only a part of Lonsdale’s life.  She was very religious, and unlike many who profess to be so she was courageous, active and steadfast in her faith.  Her husband helped her immensely in this, as well.  As we noted earlier, Kathleen’s family was fundamentalist; this clashed with her rational view of the world and cause her great consternation.  After meeting Thomas, however, the two of them embarked on an investigation of various churches and finally settled in the Quaker “Society of Friends.” With their induction into this church came a moral imperative to do good works and the conviction that war is unambiguously evil.

The latter  belief would be tested severely during World War II.  Though Lonsdale was exempt from any war duties due to her three young children, she was nevertheless required to register for civil defense.  This was unacceptable to her, and she simply refused to participate; there was no conscientious objector option for civil defense.  When the authorities finally discovered that she had not registered, they attempted to impose a small fine, but she also refused this.  I will quote from the biographical memoir [1] as to what happened next:

Complaining bitterly that she made things very difficult for them, the magistrates committed her to Holloway gaol for one month.  She has left the whole episode very fully documented, including small worried queries of her own — ‘Do the police come for one or do I just have to go to prison by myself?’  Afterwards she wrote that she was scared so stiff beforehand that prison itself came as something of an anticlimax.

She requested, and received, scientific papers and instruments to continue her work while in prison.  Upon her release, she wrote to the prison Governor and made suggestions of how to improve conditions for the prisoners, and not long after was appointed a member of the Board of Visitors for several prison institutions, which involved regular visits to inmates and serious discussions of how to improve the prison organization and prisoners’ lives.

Prison was not her only stand against war.  She joined the Atomic Scientists Association when it was founded and eventually became its Vice-President.  The goal of the organization was to educate the public about the applications and dangers of nuclear power.  She was the President of the British Section of the Women’s International League for Peace and Freedom, an organization first founded in 1915 and still around today.  She also visited the Soviet Union in 1951 as part of a Society of Friends initiative to normalize relations between the superpowers.

Lonsdale traveled extensively.  A partial list of places she traveled to includes the U.S.A., Soviet Union, China, Spain, Norway, Sweden, Denmark, Finland, Germany, India, Australia, Japan, Singapore, New Zealand, Canada, South Africa, and Mexico.  Her work was acknowledged not only abroad, but at home, as well: on March 22, 1945, Lonsdale was one of the first two women elected to be a Fellow of the Royal Society, along with Marjory Stephenson.

Lonsdale was somewhat fortunate in her life in that she had the support and encouragement of some truly remarkable men, namely Bragg and her husband Thomas.  She seems to have been acutely aware of her good fortune, and later in life gave a number of lectures about the importance of women in science and the sacrifices that women must make in taking on a scientific career.  In a wonderful and often funny 1970 lecture [2] simply titled “Women in Science,” Lonsdale lays out some of the irony and twists and turns in the treatment of women in the scientific world throughout history:

One hundred and three years ago the University of London obtained a supplemental Charter allowing women to take a Special Examination although not to be admitted to Degrees.  One disconcerting and very unexpected result of these first examinations was that the women taking them were found to excel in Classics, Mathematics and Science.

Lonsdale’s lecture is magnificent not only for its eloquence, but also for its detail.  She provides quantitative data relating to the participation of women in science at all levels, laying out the problem in an unavoidable manner.  She tactfully limits her acknowledgement of outright discrimination, but provides powerful suggestions on ways to fix the problem:

And this does suggest one way in which any country that wants to make use of all its potential women scientists and technologists could do so.  It seems to me very desireable that such women should have children.  Marriage and motherhood in their case are socially-important duties.  British government regulations are framed to ensure that a man returning to work after a period of military service in wartime is not penalized by his absence: and firms are also required to employ a certain proportion of disabled men.  Is it wholly Utopian to suggest that women scientists and science teachers who require leave of absence for family reasons should be given at least one year’s paid leave for each child as a matter of course, or that Universities, local authorities and other employers might expect to provide well-equipped nurseries and kindergartens just as they provide refectories and common rooms?  If any substantial numbers of women scientists and engineers are needed then such facilities would be well used. (They might even sometimes be useful to young fathers, especially to the students whose wives are working while they study!)  One thing I am sure of.  The kind of woman, like Professor Dorothy Hodgkin, who has managed to win a Nobel Prize for Chemistry and to bring up a family of healthy, intelligent and socially-active children, is a tremendous inspiration to other young women.

I have little that I can add to this paragraph other than to say that it blew me away when I first read it!  Remember that this was written in 1970, and was way ahead of the curve when it comes to ideas of maternity leave.  In fact, it is still quite ahead of where we are today as a society.

The issue of being a mother and a scientist was a very personal one to Lonsdale.  When her children were first born, she took a leave of absence from experimental work and focused on crystallographic tables, something she could do at home.  In general, though, her solution to the problem of work-life balance was not to sacrifice either, but simply do twice as much.

A few years before her death, Kathleen Lonsdale did a short interview with BBC Radio 4, describing concisely her research interests and outlining her work habits:

Well, I don’t need a great deal of sleep. I wake up naturally rather early in the morning.  I begin work usually at 3 or 4 am and do written theoretical work until about 6 then I leave home about half past 6 and get to college at a quarter to 9.  It’s a long train journey but sometimes I have a little sleep on the train; it’s a lovely journey I often look through the window.  And I then work until, well I get home at about a quarter to 7 in the evening.

I don’t recommend such a schedule for everybody, and suspect that only a rare select few can survive and thrive under such a grueling schedule.  This interview was done in 1967 — Kathleen was 64 years old at the time!

Lonsdale at work, taken from her BBC 4 radio interview page.

Lonsdale at work, taken from her BBC 4 radio interview page.

This brings up a fun quotation, also from the biographical memoir.  To look at her, at the BBC interview notes, one might suspect Lonsdale to be a very frail woman…

Angela Rosbaud, her secretary, teased her after one of her television appearances: ‘You look such a sweet, gentle, elderly grandmother, but you are a fraud; you are really a very tough character.’ Kathleen replied: ‘Yes, I know it is a gimmick, but it is one I like.’

There is so much more to say about Lonsdale that it is hard to finish this post.  It is perhaps best to conclude by noting that her morality really influenced the role she perceived that a scientist should play in society.  In a 1962 article [3] on “Science and ethics,” she laid out a lovely description of what a scientist should be:

The pure scientist seeks facts and accurate deduction from these facts.  He must therefore be honest, truthful and have an open mind.  He must be willing to share his knowledge with others, and since truth is not the monopoly of any one person or nation, he must have an international outlook.  He owes a debt to the past, because his own knowledge is based on free publication of the results of other people, and therefore he should dislike secrecy.  He ought to be humble, because he knows he does not have the whole of truth, partly because truth is not the monopoly of the scientist and partly because the scientific method includes a realization of the mistakes and misinterpretations of past scientists, the elimination of successive error in his own results and those of other people.

At the same time there are limits to the methods that he may use.  The trials at Nuremberg made it clear to everyone that there is some knowledge that ought not to be sought, and indeed there is some knowledge that may legally not be sought.  One must not conduct experiments that involve intolerable suffering either to man or beast.  A science teacher has a legal responsibility towards his students and the employees whose work he supervises.  He must warn them if they are dealing with dangerous poisons or with radiation that may harm them, and must show them how to avoid injury.  The scientist can afford to be patient when he is not sure of his facts: he can wait until he obtains more.

Kathleen Lonsdale was a magnificent scientist and a magnificent person.  Her achievements have been well acknowledged in the scientific community, and not only has a building named after her at University College London, but also has a crystalline diamond structure, Lonsdaleite, named after her.**  Hopefully this post will draw more popular attention to a woman who is an inspiration both scientifically and morally.

1971 photo of Kathleen Lonsdale, taken by the AP and appearing in her biographical memoir.

1971 photo of Kathleen Lonsdale, taken by the AP and appearing in her biographical memoir.

**************************

* I typically try and avoid the trap of using only the first names of women in biographical posts, as it is a common unconscious bias to refer to scientific women by their first name and scientific men by their last. However, as her name changes in the midst of the narrative here, I opted to use “Kathleen” to keep some continuity and avoid confusion.

** In a letter to Clifford Frondel, Kathleen said of her crystalline namesake: “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!”

1. Dorothy Hodgkin, “Kathleen Lonsdale (1903-1971),” from the Biographical Memoirs of the Royal Society.  This is the most detailed biography of Lonsdale available.

2. Dame Kathleen Lonsdale, “Women in Science,” Proc. Roy. Instn. Gt. Br. 43 (1970), 295-321.

3.  Dame Kathleen Lonsdale, “Science and ethics,” Nature 193 (1962), 209-214.

Other references used:

Kathleen Lonsdale, “Scientists and the People,” Bull. Atom. Sci. 14 (1958), 242-245.

M.M. Julian, “Kathleen Lonsdale and the planarity of the benzene ring,” J. Chem. Ed. 58 (1981), 365-366.

M. Baldwin, “‘Where are your intelligent mothers to come from?’ Marriage and family in the scientific career of Dame Kathleen Lonsdale FRS (1903-71),” Notes Rec. R. Soc. 63 (2009), 81-94.

The Principles of a Quaker crystallographer,” New Scientist, August 1, 1957, pp. 21-22.

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One Response to Kathleen Lonsdale: Master of Crystallography

  1. qisaiman says:

    Wonderful narrative; Will look into the detailed work by Kathleen Lonsdale. Just one minor revision: the X-ray wavelength commonly used in Crystallography is about 0.1 nanometer, not 0.01 as mentioned. (Cu K_alpha line: 1.540 angstrom)

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