Walther Gerlach

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Memorial plaque on the house of the Physikalischer Verein

Walther Gerlach (born August 1, 1889 in Biebrich am Rhein , † August 10, 1979 in Munich ) was a German physicist and university professor.


Walther Gerlach was born in Biebrich as the son of the hygienist Valentin Gerlach and his wife Marie geb. Niederhaeuser (1863–1941). He is the older brother of the pathologist Werner Gerlach and the doctor Wolfgang Gerlach (twins).

Gerlach began his studies at the Eberhard Karls University in Tübingen in 1908 and was active in the Corps Borussia Tübingen . It was in 1912 under Friedrich Paschen to Dr. rer. nat. did his doctorate and habilitation in 1916. At that time he was busy measuring the Stefan-Boltzmann constant . From 1915 to 1918 he did military service and was last in Berlin. From 1917 he was a private lecturer at the Georg-August University in Göttingen. 1919/20 he worked in the physics laboratory of the paint factory in Elberfeld (later Bayer AG). In 1921 he became associate professor at the new Johann Wolfgang Goethe University in Frankfurt am Main under Richard Wachsmuth . Around 1921 he and Otto Stern designed the Stern-Gerlach experiment to prove directional quantization . The experiment was successfully carried out by Gerlach in Frankfurt in February 1922. Gentner writes that this experiment, the result of which Niels Bohr had correctly predicted "in contrast to others" (which is why Gerlach reported the result of the experiment in a telegram to Stern in Rostock with the words Bohr was right ), a for the time " The highest level of experimental art "required. and further "with this the directional quantization was proven". On a postcard. The critical theorist Wolfgang Pauli wrote to Gerlach on February 17, 1922, Pauli wrote "Hopefully the unbelieving star will also be convinced of the directional quantification". Gerlach was proposed for this work, together with Stern, for the Nobel Prize in Physics in 1925 and in eleven other years , but never received it. According to Horst Schmidt-Böcking , the Nobel Committee probably had concerns about compromising itself because of Gerlach's participation in the Reich Research Council and the uranium project towards the end of the war. In 1944, when the Nobel Prize for Stern was being discussed, it was suggested by the influential physicist Manne Siegbahn . The Stern-Gerlach attempt was not explicitly mentioned in the official justification for Stern, but it certainly played a decisive role, as the commendation by committee member Eric Hulthén on Swedish radio in 1944 showed. Schmidt-Böcking reconstructed the original experimental setup for the Stern-Gerlach experiment; the original was lost in World War II. The reconstruction and preserved originals (a microscope from Stern and vacuum pumps) were shown at an anniversary exhibition at the University of Frankfurt in 2014.

In 1924/25 he returned to Tübingen as professor and successor from Paschen, among others on the recommendation of Albert Einstein . In 1929 Gerlach received the chair for experimental physics at the Ludwig Maximilians University in Munich as the successor to Wilhelm Wien (at the special instigation of Arnold Sommerfeld ). He held the chair until his retirement in 1957. He was director of the 1st Physics Institute at the University of Munich. In 1940 he was elected a member of the Leopoldina . From 1943 he headed the physics department and the working group for nuclear physics in the Reich Research Council . Initially he was the Reichsmarschall's agent for nuclear physics for the German uranium project , and from 1944 he was an agent for nuclear physics . As part of this, he also brought a number of young physicists from the front. At the end of the war he was interned by the Allies in Farm Hall as part of Operation Epsilon . From 1946 to 1948 he was a professor at the University of Bonn. From 1948 to 1951 he was rector of the Ludwig Maximilians University, where he rebuilt the physics institute. From 1949 to 1951 he was also the first president of the Fraunhofer Society . From 1951 to 1961 he was Vice President of the German Research Foundation (DFG) and from 1956 to 1957 President of the German Physical Society (DPG). From 1937 to 1946 Gerlach was a member of the Senate of the Kaiser Wilhelm Society .

After the war he was active in rebuilding the natural sciences in Germany. He was involved in setting up the German National Academic Foundation, was a senator of the Max Planck Society and was involved in setting up the Physikalisch-Technische Bundesanstalt in Braunschweig. Gerlach was co-initiator and signatory of the Tübingen resolution of October 1, 1951: The demand for increased performance, which was justifiably made after 1945, was in danger of suffocating intellectual life with the abundance of material. "The penetration of the essentials of the teaching subjects has absolute priority over any expansion of the material area." In 1957 he signed the declaration of the Göttingen Eighteen , a group of 18 nuclear physicists who opposed the planned nuclear armament of the Bundeswehr .

He decided in 1923 with Alice Golsen the radiation pressure . In addition, he dealt with the temperature dependence of magnetic properties with applications in industry, the connection between atomic structure and magnetism, the photoelectric effect , thermal radiation and he determined Bohr's magneton . From 1930 to 1936 he published a three-volume monograph on quantitative chemical spectral analysis . He later dealt with natural and human (atomic bomb tests in the 1950s) radioactivity in the environment. In public lectures in the 1950s, he advocated stopping atomic bomb tests.

Gerlach wrote some popular science books on physics and the biographies of Otto Hahn (with whom he was close friends for many years), Johannes Kepler and Michael Faraday . He was editor of the Fischer-Lexikon Physik and wrote sections on the history of physics in the Propylaea world history . For a long time Gerlach dealt intensively with Kepler and was President of the Kepler Society in Kepler's birthplace, Weil der Stadt . In Munich he was known for the large experimental physics lecture, with demonstration experiments that approached the well-known Göttingen lecture by Robert Wichard Pohl .

Gerlach was first married to Mina Metzger (born 1889) on September 29, 1917; they had a daughter Ursula (born 1918). In his second marriage (Munich, April 18, 1939) he was with the pediatrician Dr. med. Ruth Probst (1905–1994) married. He died in Munich in 1979 and was buried in the forest cemetery there.


Walther Gerlach.JPG


  • The chemical emission spectral analysis , 3 vol. Voss, Leipzig 1930, 1933, 1936
  • The experimental foundations of quantum theory , Vieweg, Braunschweig 1921. ( digitized at archive.org )
  • Atomic degradation and atomic construction: the physical analysis of atoms , Jena: Fischer 1923
  • Matter, electricity, energy: Fundamentals and results of experimental atomic research , Dresden: Steinkopff 1926.
  • The importance of the purest iron in crystallized form for the problem of ferromagnetism . In: Wilhelm Geibel (ed.): Festschrift for the 70th birthday of Dr. phil. Dr. ing. eh Wilhelm Heraeus , Hanau: GM Albertis Hofbuchhandlung Bruno Clauss 1930, pp. 27–33.
  • The free electron , in: Carl Ramsauer (Hrsg.): The free electron in physics and technology , Springer 1940
  • The quantum theory: Max Planck, his work and its effect; with a bibliography of the works of Max Planck , Bonn: Universitätsverlag 1948
  • (Ed.): The tongue loosening nature: Life and performance of great researchers , Munich: Ehrenwirth 1969 (first edition 1967), series: the modern non-fiction book; Vol. 84.
  • with Martha List: Johannes Kepler . 2nd Edition. Piper, Munich 1980, ISBN 3-492-00501-2 .
  • with Dietrich Hahn : Otto Hahn . A researcher's life in our time. Wissenschaftliche Verlagsgesellschaft (WVG), Stuttgart 1984. ISBN 3-8047-0757-2 .
  • (as ed., with the collaboration of Josef Brandmüller): The Fischer Lexicon: Part 19: Physics , new edition 239. – 243. Tausend, Fischer-Taschenbuch-Verlag, Frankfurt am Main 1978, ISBN 3-596-40019-8 .
  • MR. Bachmann, Helmut Rechenberg (editor): Walther Gerlach (1889-1979). A selection from his writings and letters , Springer Verlag 1989
  • Physics of Daily Life - A Guide to Physical Thinking and Understanding Physical Development , Springer 1957, Fischer Bücherei, 1971
  • Michael Faraday: (1791 - 1867) on the 100th anniversary of death , Oldenbourg 1968
  • The language of physics , Bonn: Dümmler 1962
  • Humanity and scientific research , Vieweg 1962
  • Physics in intellectual history and education , Cologne, Aulis 1964

See also


  • Rudolf Heinrich, Hans-Reinhard Bachmann (arrangement): Walther Gerlach. Physicist, teacher, organizer. Documents from his estate , an exhibition in the Deutsches Museum on the occasion of the experimental physicist's 100th birthday, July 26 - November 29, 1989, ISBN 3-924183-12-0 .
  • Josef Georg Huber: Walther Gerlach (1889 - 1979) and his path to becoming a successful experimental physicist until around 1925 , Rauner, Augsburg 2015 (Algorism, Issue 82), ISBN 978-3-936905-58-8 .
  • Richard von Schirach : The night of the physicists. Heisenberg, Hahn, Weizsäcker and the German bomb . Berenberg, Berlin 2012, ISBN 978-3-937834-54-2
  • Excerpts from an exchange of letters between Richard Gans and Walther Gerlach at Klaus Schlüpmann: The past in the field of vision of a physicist, Hans Kopfermann 1895–1963, chapter 'Formation phase' of the power cartel
  • Helmut Rechenberg: Walther Gerlach on the 90th, Physikalische Blätter, Volume 35, August 1979, 370–374, doi : 10.1002 / phbl.19790350805 (free full text)
  • Helmut Rechenberg: Walther Gerlach memories on the occasion of his 100th birthday, Physikalische Blätter, August 1989, doi : 10.1002 / phbl.19890450804 (free full text)
  • Wilhelm Schütz: Personal memories of the discovery of the Stern-Gerlach effect . In: Physical sheets . tape 25 , 1969, p. 343–345 , doi : 10.1002 / phbl.19690250802 (free full text).
  • Wolfgang Gentner : Commemorative Words for Walther Gerlach, in: Orden Pour le Mérite for Sciences and Arts, Speeches and Commemorative Words, Volume Sixteenth 1980, Lambert Schneider Verlag, Heidelberg, Online

Web links

Commons : Walther Gerlach  - Collection of images, videos and audio files

Individual evidence

  1. a b c Grave of the Gerlach family in the Munich forest cemetery (Grabfeld 108, location , pictures )
  2. Kösener Corpslisten 1930, 127/340; retired after World War II.
  3. a b c d e f g Wolfgang Gentner, memorial words for Walther Gerlach, Orden Pour le Mérite, Volume 16, 1980, pp. 47–53
  4. ^ Nomination Database. Nobel Foundation , accessed on July 13, 2019 (Stern and Gerlach were jointly nominated for the Nobel Prize in 1925, 1927–1932, 1934, 1936, 1937, 1940 and 1944. Stern received it in 1944 (for 1943).).
  5. Horst Schmidt-Böcking, Interview in Research Frankfurt, No. 1, 2014, p. 75
  6. Horst Schmidt-Böcking, Alan Templeton, Wolfgang Trageser (ed.), Otto Sterns Gesammelte Briefe, Volume 2, Springer 2019, p. 344. There it is also stated that it cannot be proven that Gerlach switched to his role was due in the time of National Socialism.
  7. Astrid Ludwig, The Forgotten Nobel Prize Winner , Frankfurter Rundschau, Frankfurter Rundschau, December 28, 2010. This is Otto Stern. Schmidt-Böcking's replica was in his office at the time. He only has an original Stern microscope that he received from his niece.
  8. Otto Stern , Frankfurter Personenlexikon 2019
  9. Text of the Göttingen Declaration 1957 at uni-goettingen.de
  10. Holger Krahnke: The members of the Academy of Sciences in Göttingen 1751-2001 (= Treatises of the Academy of Sciences in Göttingen, Philological-Historical Class. Volume 3, Vol. 246 = Treatises of the Academy of Sciences in Göttingen, Mathematical-Physical Class. Episode 3, vol. 50). Vandenhoeck & Ruprecht, Göttingen 2001, ISBN 3-525-82516-1 , p. 91.