Friedrich Kohlrausch (physicist)

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Friedrich Kohlrausch

Friedrich Wilhelm Georg Kohlrausch (born October 14, 1840 in Rinteln , † January 17, 1910 in Marburg ) was a German physicist and physical chemist . He was the son of Rudolf Kohlrausch (1809-1858), brother of Wilhelm Kohlrausch and grandson of Friedrich Kohlrausch .

Scientific career

Friedrich Kohlrausch in Würzburg

Kohlrausch studied in Erlangen and Göttingen , where he received his doctorate in 1863 under Wilhelm Eduard Weber on the "elastic aftereffects of torsion". In 1864 he became a lecturer at the Physics Association in Frankfurt am Main . Since his studies in Göttingen he was a member of the Brunsviga fraternity . Further stations:

Kohlrausch was a member of the Academy of Sciences in Berlin and from 1895 to 1905 - as successor to Hermann von Helmholtz - President of the Physikalisch-Technische Reichsanstalt (PTR) in Charlottenburg . In 1899 he was appointed full honorary professor at Berlin University . In 1896 he was accepted into the order Pour le mérite for sciences and arts , elected to the American Academy of Arts and Sciences in 1900, and to the National Academy of Sciences in 1901 . Since 1894 he was a corresponding member of the Russian Academy of Sciences in Saint Petersburg . In 1907 he became an Honorary Fellow of the Royal Society of Edinburgh .

His doctoral students include the American physicist Carl Barus (1856–1935, doctorate in 1879), Erasmus Kittler (1852–1929, doctorate in 1880) and Walther Nernst (1864–1941), who did his doctorate with him in Würzburg in 1887.

Services

His work in the fields of theory, measurement methods and instruments and experiments have mainly concentrated on the electrical and magnetic properties (determination of the ohm and the electrochemical equivalent).

From 1875 he opened up the new field of physical chemistry, solutions , especially their electrolytic conductivity : Kohlrausch's law of square roots, determination of the ion product of water with Heydweiller, development of the first conductometer for conductivity measurement of electrolytes, determination of the solubility product of poorly soluble salts, determination the change in conductivity as a function of temperature, calculation rule for determining the migration speeds of ions from the limit conductivity during electrolysis , as well as thermoelectricity and thermal conduction , total reflection of light and elasticity .

With his investigations on the elastic aftereffect, he took up an observation by Wilhelm Eduard Weber ; To describe the results, he used the Kohlrausch function proposed by his father for the electrical aftereffect .

family

He married Hermine Schilling in Göttingen in 1867 , a daughter of the doctor Dr. Eduard Schilling. The couple had one son and four daughters, including:

  • Eduard (February 4, 1874 - January 22, 1948) ∞ Helene Carl (1877–1971)
  • Marie (* 1869) ∞ Wilhelm Hallwachs (1859–1922), physicist,

Fonts (selection)

  • Guide to practical physics (Leipzig 1870).
  • The conductivity of electrolytes (Leipzig 1898).

The Physikalisch-Technische Bundesanstalt (PTB) and its predecessor institution, the PTR, make the scientifically and historically significant "Kohlrausch" available for download in its last 24th edition from 1996 (Teubner-Verlag).

The estate of FW Kohlrausch is in the archive of the Deutsches Museum in Munich .

literature

Web links

Commons : Friedrich Kohlrausch  - Collection of images, videos and audio files
Wikisource: Friedrich Kohlrausch  - Sources and full texts

Individual evidence

  1. see Hessisches Staatsarchiv Marburg (HStAMR), Best. 915 No. 5699, p. 54 ( digitized version ).
  2. Physikalische Blätter, Volume 46, Issue 10; doi : 10.1002 / phbl.19900461010
  3. Heinz Fricke (Ed.): 150 Years of the Physikalischer Verein Frankfurt a. M. 1st edition. Physikalischer Verein, Frankfurt 1974, DNB  750868783 , The lecturers of the association until 1886, p. 108 .
  4. ^ History of physics in Würzburg
  5. ^ Foreign members of the Russian Academy of Sciences since 1724. Friedrich Wilhelm Georg Kohlrausch. Russian Academy of Sciences, accessed September 22, 2015 (Russian).
  6. ^ Fellows Directory. Biographical Index: Former RSE Fellows 1783–2002. (PDF file) Royal Society of Edinburgh, accessed December 28, 2019 .
  7. Axel W.-O. Schmidt: An American in Würzburg: How Carl Barus became a member of the Würzburg fraternity Arminia in 1876. In: Tempora mutantur et nos? Festschrift for Walter M. Brod on his 95th birthday. With contributions from friends, companions and contemporaries. Edited by Andreas Mettenleiter , Akamedon, Pfaffenhofen 2007 (= From Würzburgs Stadt- und Universitätsgeschichte, 2), ISBN 3-940072-01-X , pp. 297-307