Agnes Pockels pioneered study of the physics of surface films.
In 1932, Ostwald published a review of her work as a tribute on her 70th
birthday and wrote
... every colleague who is now engaged on surface layer or film research will recognize that the foundation
for the quantitative method in this field... had been laid by observations fifty years ago. --- W. Ostwald, Koll. Zeit. 58: 1 (1932)[from Giles and Forrester
Ostwald was refering to the work of Pockels. In 1881, she observed the streaming of currents when salts were put into
solution and, by attaching a float to a balance, measured the increase in
... For ten years she
went on studying the properties of surfactants and surface tension of liquid
solutions ... in her own home. She sent her results to the professor of
physics of the University of Goettingen who seemed not to appreciate them.
Lord Rayleigh began to publish on this subject, she wrote to him
about her work. The letter was written in German. Rayleigh found it so remarkable he asked his wife to translate it into English and sent it to be
published in Nature.
was published March 12, 1891 with the following introductory
paragraph written by Lord Rayleigh:
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 respecting the
behaviour of contaminated water surfaces. The earlier part of Miss Pockels' letter covers nearly the same ground
as some of my own recent work, and in the main harmonizes with it. The later sections seem to me very
suggestive, raising, if they do not fully answer, many important questions. I hope soon to find opportunity for
repeating some of Miss Pockels' experiments.
She published numerous articles after Lord Rayleigh published her letter in
Nature. These are listed in a biography by M. Elizabeth Derrick
in Women in Physics and Chemistry [pc 1982md].
The following quotations are taken from Derrick's article.
"The surface balance technique Pockels developed became useful in physical
chemistry for determining the size and shape of organic molecules at a time when
X-ray diffraction was not yet available.
Her surface film balance technique is the basis for the method later developed by
Langmuir and often referred to as a Langmuir trough. This technique is still used
by surface chemists. "
"Pockels's description of how she introduced water-insoluble compounds to the
water surface by dissolving them in an organic solvent, applying drops of the
solution, and then allowing the solvent to evaporate is now the standard technique
used. Clean surfaces are a major problem for surface experimentation... The
technique she developed for ensuring a clean surface has become standard
"Observations of the so-called Pockel's point, the minimum area occupied by a
monomolecular surface film, about 20 angstroms."
"Surface Tension," Nature 43: 437 (1891).
This is the first of her many publications. She published over a forty year period - until 1931;
[pc 1982md] for a list of her publications.
Laura Leonard Prize 1931, with Henri Devaux
- for qualitative investigation of the
properties of surface layers and surface films.
Honorary Doctorate, Carolina-Wilhelmina University, Brunswick, Germany 1932.
Pockels remained at home and, besides doing physics experiments,
took care of the house and her parents.
Municipal High School for Girls, Brunswick, Germany
Regarding a university education, Pockels wrote:
(while in high school), I had already developed a passionate interest in the
natural sciences, especially in physics, and would have liked to become a
student, but at that time women were not accepted for higher education and
later on, when they started to be accepted, my parents nevertheless asked me
not to do so. [ci1971cg]
Giles and Forrester have written a very interesting account of Pockels'
career[ci1971cg] - some excerpts:
"Agnes Pockels' researches, developed almost entirely independently, are
meritorious by any standard. They show a clarity of thought and observation, and
strictness of scientific approach remarkable for a girl of her years who had no
formal training. When examined however against the background of her life they
become truly astonishing.
"Pockels' family lived for many years in the malaria infected region of North Italy
while her father served in the Austrian army. As a result of this, the entire family
suffered adverse health even after returning to Brunswick in 1871. Pockels took
on the role of household manager and nurse as her parents' health deteriorated. Her diary illustrates the difficulties she faced in trying to maintain her own
health, the health of her parents and continue her scientific research at the same
"Pockels' parents refused to allow her to proceed to higher education so she found
other routes to gain scientific knowledge. ...
and wrote in
I attempted to continue my education by my own devices, first of all by the
use of a small text book by Pouillet-Müller and since 1883 by means of book
provided by my brother, Friedrich Pockels, who is three years younger than I
and eventually became a professor of physics, but who at that time was a
student at Göttingen. However, this type of training did not take me far in
respect of the mathematical approach to physics, so that I much regret to
have but little knowledge of theoretical matters. "
Field Editor: Professor Gary A. Williams