Leonhard Sohncke

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Leonhard Sohncke (between 1886 and 1897)

Leonhard Sohncke (born February 22, 1842 in Halle , † November 1, 1897 in Munich ) was a mathematician , scientist and professor of physics in Karlsruhe , Jena and Munich.

Life

Leonhard Sohncke was the second son of the mathematician Ludwig Adolf Sohncke (1807-1853). Leonhard Sohncke studied mathematics and natural sciences at the University of Halle from 1859 . In 1865 he became a teacher at a grammar school in Königsberg, where he continued his studies at the University of Königsberg . His doctorate as Dr. phil. In Halle he finished in 1866 with a mathematical thesis, which goes back to the suggestion of Heinrich Eduard Heine , “De aequatione differentiali seriei hypergeometricae”.

In 1866 he married his cousin Elise Bernhardi. They had two daughters, Dora and Elsbeth (married Pastor Ernst Böhme in 1888 ).

In 1869 he completed his habilitation with Franz Ernst Neumann in Königsberg with a thesis on the cohesion of rock salt.

In 1871, on the recommendation of Gustav Robert Kirchhoff , Leonhard Sohncke became professor of experimental physics at the Karlsruhe Polytechnic, now the Karlsruhe Institute of Technology , and also took over the management of the local meteorological observatory. In 1871 he became a co-founder of the Upper Rhine Geological Association .

In 1883 he became a full professor of physics at the University of Jena and the first head of the physical institute there.

Physics institute of the University of Jena around 1900 (source: building archive of the FSU Jena)

In 1886 he moved to Munich to the chair of experimental physics (successor to Wilhelm von Beetz ) and headed the physics department at the Technical University of Munich until his death in 1897 .

Act

One focus of Sohncke's research was solid-state physics , where he developed theories of crystal structure . He expanded the 14 point grids ( Bravais grids ) introduced by Auguste Bravais to 65 space groups ( Sohncke space groups ), which only contain axes of rotation and screw axes. In the field of birefringence and polarization he worked with Ernst Abbe and Siegfried Czapski . Together with Albert Wangerin, he published works on optical interference and Newton's rings .

Demonstration model by Sohncke to illustrate the “chiral” room groups
Replica of the demonstration model by Sohncke

Another focus was meteorology , where he dealt with storm electricity and weather forecasts. He confirmed the discovery of Michael Faraday that electricity is generated by the friction of water on ice and proved that this effect is an essential source of electrical phenomena in the atmosphere (Faraday-Sohncke effect). He was one of the pioneers of scientific balloon flights, co-founder and chairman of the Munich Association for Airship Travel. Together with Sebastian Finsterwalder , he published essential meteorological results of these balloon trips.

For teaching, Sohncke developed a series of experiments and descriptive models. In close contact with Adolf Ferdinand Weinhold , the "Nestor of Electrical Engineering" at the TU Chemnitz, he introduced electrical engineering lecture experiments.

Blackboard at the former Physics Institute of the University of Jena

Honors

He became an extraordinary member of the Bavarian Academy of Sciences in 1887 and a full member in 1889 . In 1892 he was awarded an honorary doctorate from the University of Padua .

In his honor there is the Sohncke-Strasse in Munich and the Leonhard-Sohncke-Weg in Karlsruhe. At the former first physics institute in Jena, Neugasse 24, the construction of which was planned by Ernst Abbe and implemented by Sohncke, a plaque commemorates him.

Works (selection)

  • De aequatione differentiali seriei hypergeometrica , Halle, 1866
  • On the cohesion of rock salt in crystallographically different directions , doctorate, Königsberg 1869, see also Annals of Physics and Chemistry, CXXXVII, No. 6, p. 12 ff, 1869
  • On the theory of the optical rotation of crystals . Mathem. Annals by C. Neumann. Vol. IX, 1870, pp. 504-529.
  • The unlimited regular point systems as the basis of a theory of the crystal structure . 83 pages. 2 plates, Karlsruhe 1876. Separate print from the 7th issue of the negotiations of the naturwissensohaftl. Karlsruhe Association.
  • Universal model of space grids . Repertory for Experimental Physics. Vol. XII. 1876. 6 pages.
  • Development of a theory of the crystal structure . BG Teubner, Leipzig 1879
  • An apparatus for studying Newton's rings , Ann. Phys. 13, 1881
  • Sohncke, L., Wangerin A. New Studies on Newton's Rings , Ann. Phys. 12, 1881
  • L. Sohncke, A. Wangerin, About interference phenomena on thin, in particular wedge-shaped, leaflets , Ann Phys. 256 (19), 177-227 (1883) and 256 (11), 391-425 (1883)
  • Common lectures from the fields of physics , Jena, Gustav Fischer Verlag, 1892.
  • Extended theory of the crystal structure , Zeitschrift für Kristallographie 14, 426–446 (1888)
  • Thunderstorm electricity and ordinary air electricity , meterol. Journal 5, 1888
  • Thunderstorm studies based on balloon flights , Akademische Abhandlungen 18, 1895, Munich
  • Finsterwalder, S., Sohncke, L. Scientific trips of the Munich Association for Aviation , Meterolo. Zeitsch. 11, 1894, pp. 375-376
  • About the importance of scientific balloon flights , ceremonial speeches from November 15, 1894 Munich, Munich, publishing house of the KB Academy, 1894.

literature

  • Paul Seidel: Life and works of LEONHARD SOHNCKE (1842-1897), a co-founder of the Upper Rhine Geological Association , Jber. Mitt. Oberrhein. geol. Ver., NF, 91, 101-112, 2009.
  • Andreas Flitner , Joachim Wittig (Ed.): Optics - Technology - Social Culture. Siegfried Czapski, companion and successor of Ernst Abbes. Letters, writings, documents . Hain-Verlag, Rudolstadt 2000, ISBN 3-930215-91-8 .
  • Fritz Erk: Leonhard Sohncke , Meteorologische Zeitschrift Volume 15 (1898), pp. 81–84.
  • Sebastian Finsterwalder , Hermann Ebert : Leonhard Sohncke , Annual Report of the Royal Technical University in Munich 1897/98, Appendix pp. 1–21.
  • Siegmund Günther:  Sohncke, Leonhard . In: Allgemeine Deutsche Biographie (ADB). Volume 54, Duncker & Humblot, Leipzig 1908, pp. 377-379.

Web links

Commons : Leonhard Sohncke  - Collection of images, videos and audio files
personal data
SURNAME Sohncke, Leonhard
BRIEF DESCRIPTION German university professor, professor of physics
DATE OF BIRTH February 22, 1842
PLACE OF BIRTH Hall
DATE OF DEATH November 1, 1897
Place of death Munich