Agnes Pockels never took any formal studies. Nevertheless, the research of this self-taught chemist has received international recognition. In 1932, she was awarded an honorary doctorate from Braunschweig University, Germany.
For many people, greasy dishwater is an unpleasant part of everyday household chores. However, for housewife and chemist Agnes Pockels, it was a source of inspiration for scientific experiments. She developed test equipment for measuring surface tension and thus created the basis for clarifying many boundary surface phenomena.
"... I was not able to directly publish (the scientific results), partially because the publishing houses here were unlikely to accept contributions from a woman and partially because I had no sufficient information regarding work carried out by others on the same topic", Agnes Pockels writes in a letter to the British physicist and later Nobel Laureate, John William Strutt, who is known as Lord Rayleigh. This statement shows the modest opinion she had about her kitchen table research that constitutes the basis of today's knowledge about boundary surface phenomena.
Agnes Pockels was born on 14 February 1862 in Venice as the daughter of Theodor Pockels, an Austrian professional soldier and his wife Alwine. At that time, malaria was common in northern Italy, and the Pockels family were not spared from this disease either. After the early retirement of the father, the family moved to Braunschweig where Agnes Pockels attended the municipal secondary school for girls. From an early age, she was interested in physics and often discussed it with her brother Friedrich, who was three years younger. Later he became a physics professor at the University of Göttingen and supplied her with specialist books. Agnes Pockels would have liked to study physics as well, but women were not allowed to attend a university. When they were - later on - permitted to study at universities, she stood back because of her father's wishes. Throughout her lifetime, she was in charge of the housekeeping and care of the sick in the family home.
Experimenting with dish water
"... every day, millions of housewives were unhappy to see greasy dish water and just wanted to get rid of it, but it inspired this very person to make observations and finally also work on scientific treatises", her sister-in-law, Elisabeth Pockels, wrote. In her research, she worked with surface tension and wetting phenomena. She used simple gadgets to develop measuring equipment that she called Schieberinne (literary: shift trog). She succinctly wrote in her diary: "1880 or -81: I have discovered the abnormal behaviour of the water surface. 1882: I have developed the Schieberinne (trog). 1883: I had a large Schieberinne made." Irving Langmuir developed Pockels' "Schieberinne" further into the so-called Langmuir trog that is still used today for quantitative analyses of surface films. In 1932, he received the Nobel Prize for his work. Charles Giles and Stanley Forester wrote the following: "When Langmuir received the Nobel Prize for Chemistry in 1932 for his investigations of monolayers on solids and on liquids, part of his achievement was founded on original experiments first made with a button and a thin tray, by an 18-year-old lady without any formal scientific training."
Over a ten-year period, Pockels carried out meticulous measurements, without receiving any inspiration or exchange of ideas from other scientists. In 1890, she read an article by Lord Rayleigh who also worked on surface phenomena. She wrote him a twelve-page letter that included her results with the permission to use them. "I completely leave it up to you to use my modest work and this information..." Rayleigh recognised the value of this work and instantly did all he could to publish the letter in "Nature". Two months later, Pockels' letter was published together with Rayleigh's cover letter to the publisher. He writes in his letter: "I shall be obliged if you can find space for the accompanying translation of an interesting letter which I have received from a German lady, who with very homely appliances has arrived at valuable results regarding the behaviour of contaminated water surfaces."
Reproduction of the original Schieberinne built by Agnes Pockels
The publication of her work inspired her to further pursue scientific activities. With her characteristic accuracy she investigated the surface forces of mono-molecular films, the adhesion of different liquids on glass, and the boundary-surface tension of emulsions and solutions. She published her results, among others, in Nature, Wissenschaftliche Rundschau, and Annalen der Physik. As a result, she also gained the recognition of German physicists and was invited to hold scientific lectures. In addition to her work on surface phenomena, she also investigated other issues. In 1902, she published a translation of "The Tides and Kindred Phenomena in the Solar System" by Georg Howard Darwin and in 1909 a philosophical treatment in Annalen der Naturphilosophie.
In the early 1900s, her sick parents required more and more care. Therefore she was not able to continue working at the Physikalische Institut of Technische Hochschule Braunschweig. In 1906, her father died, then in 1913 her brother passed away, and one year later her mother died. During World War I, she lost contact to the scientific community and stopped carrying out experiments. However, throughout all the years before, this exceptional scientist kept following her interests in spite of family obligations and social constraints.
When Agnes Pockels turned 70, she finally received public recognition. In 1931, she was awarded the Laura-R.-Leonard Prize of the Colloid Society, and in 1932 she received an honorary doctorate in engineering from Technische Hochschule Braunschweig.
Since 1993, Braunschweig Technical University (TU) has awarded the Agnes-Pockels Medal. This science award honours people who have made outstanding contributions to the further development of Braunschweig Technical University, as well as promoting research and teaching - in particular that of women.
Laureate 2003: Ingeborg Wender (PhD), Institut für Pädagogische Psychologie at Braunschweig Technical University.
This text is the translation of an article authored by Andrea Kruse and Sonja M. Schwarzl. Original title: "Zum Beispiel Agnes Pockels", published in "Nachrichten aus der Chemie, 06, 2002. Reproduced by courtesy of the authors.
Picture credits. Portrait of Agnes Pockels, Replica of the Schieberinne, and image of the Agnes-Pockels Medal: Archive of Braunschweig Technical University.