Paul CoxonOvjeren akaunt

Kathleen Yardley was born in Newbridge, County Kildare. She was the youngest of 10 children. Her father worked for the Post Office and was quite well read. They weren't rich, and four of her siblings died in infancy.

Her parents split up when Kathleen was five, so in 1908 her mother, a strict Baptist, moved with the children back to England and settled in Essex. Kathleen went to Downshall Elementary School then won a scholarship to County High School for Girls at Ilford.

Kathleen was pretty good at most lessons, but her high school didn't offer physics, chemistry or maths so she had to join the boys school nearby. She was the only girl in the class.

There were only two physics students in her final year. Kathleen Yardley came top in the BSc examination and graduated with a first in 1922. This brought her to the attention of the examiner, a certain Sir W H Bragg, Professor of Physics at @UCL https://en.wikipedia.org/wiki/William_Henry_Bragg …

Yardley worked on physical and structural properties of crystals. Together with William Astbury, she worked on the relationship between X-ray dirraction patterns and the 3d arrangement of crystals. This turned out to be a very useful & important tool for X-ray crystallographers.

Kathleen & Thomas got wed, but he didn't marry "to get a free housekeeper" and expected Kathleen to continue research. When he got a job at Leeds Kathleen joined the physics dept there. Here's a great paper by @Melinda_Baldwin on KL's marriage & career: http://rsnr.royalsocietypublishing.org/content/63/1/81 

While at Leeds Lonsdale embarked on what she regarded as her most "fundamental and satisfying piece of research" - investigating the structure of benzene http://www.armstrongwynne.org/benzene.html 

Lonsdale was no organic chemist, but benzene is one of the most important organic chemical compounds. Its precise structure had been debated by chemists for decades.

Some people (including Bragg) thought that that hexagonal ring of benzene was puckered, like in diamond. Lonsdale’s X-ray crystallography experiments showed it was flat, but also had an evenly distributed cloud of electrons, sharing the three double bonds.

By now, Thomas had a new job as a research scientist in Harmondsworth, so after less than three years in Leeds, and with another baby due, they moved back to London.

Nancy was born in July and KL's second paper on the benzene structure came out in October 1931. Although she couldn't *definitely* say if benzene in this case was flat, it the first time Fourier methods had been used to analyse an organic compound http://rspa.royalsocietypublishing.org/content/133/822/536?cct=1790 …

Right. Time for lunch. Back in half an hour, which is fitting as Lonsdale herself specialised in making meals that only took 30 minutes to prepare, as mentioned in her Reminiscences from 1962: https://www.iucr.org/__data/assets/pdf_file/0018/774/lonsdale.pdf …

So now back in London, with two children to raise (Thomas helped out a bit) Lonsdale could continue theoretical work at home. Bragg was *well* chuffed to have her back and arranged funds for a childminder to help Lonsdale return to @Ri_Science full timehttps://twitter.com/jesswade/status/957338041324130306 …

During this period at the RI, Lonsdale occupied Faraday's old room, and worked on the theoretical framework for crystallography, compiling Structure Factor Tables which make it easier for others people to solve crystal structures.

Lonsdale's handwritten book of Structure Factor Tables is one of my favourite thingshttps://twitter.com/Ri_Science/status/878199505342083072 …

Like most postdocs (oh yeah, she got a DSc from London), Lonsdale relied on short term grants. After her 3rd child, Stephen, was born in 1934 she went back to the RI, there was no X-ray apparatus for her, but there was a big magnet, so she changed fields (magnetic fields lol)

As WW2 got underway, Lonsdale was one of the few researchers still at the RI. She had become a Quaker with Thomas some years before and, with early memories of WWI Zeppelins falling out the sky above her childhood home, a committed Pacifist.

Lonsdale regarded her roles of scientist, mother and Quaker as being intimately connected.

Lonsdale refused to register for fire-watching duties against incendiary bombs from enemy planes. As the mother of three children under the age of fourteen she'd have been exempt, but she regarded it as a fundamental infringement of civil liberties and went to court.