Wilhelm Hallwachs (physicist)

Robert Sterl : Portrait of Wilhelm Hallwachs (1907)

Wilhelm Ludwig Franz Hallwachs (born July 9, 1859 in Darmstadt , † June 20, 1922 in Dresden ) was a German physicist .

Career

In 1886 Heinrich Hertz had discovered the external photo effect . Hallwachs continued Hertz's investigations in 1887. Because of his results, the external photo effect was known for a long time as the Hall wax effect .

From 1893 to 1922 he was professor for theoretical experimental physics at the Technical University of Dresden . In 1921 and 1922 he was elected rector of the Dresden University of Technology. His successor in office was Harry Dember . Since 1905 he was a full member of the Saxon Academy of Sciences .

With the investigation of the photo effect , he laid the foundation for the development of the photocell , photoelectricity and Albert Einstein's light quantum hypothesis (see also Photon ).

family

Hallwachs was the son of the lawyer and MP Ludwig Hallwachs and his wife Charlotte Emilie Wilhelmine, née Hoffmann (1826–1863). He married Marie Kohlrausch (1869 – after 1930) in Strasbourg in 1890, the daughter of the professor of physics and later president of the physical and technical Reichsanstalt Friedrich Kohlrausch (1840–1910) and Hermine nee Schilling. Their daughter, Helene Huch-Hallwachs, b. Hallwachs married Karl Huch-Hallwachs (* 1893), the director of the Koch-Stenzel electrical works. The musician and composer Karl Hallwachs (1870–1959), the actor and singer Reinhard Hallwachs (1833–1872) and the Royal Prussian Colonel General and Adjutant General Friedrich von Scholl (1846–1928) were cousins.

Fonts

• About the electromotive force, the resistance and the efficiency of charge columns (accumulators) . Diss., Strasbourg 1883.
• Electrometric investigations . Habil. Writing, Leipzig 1885.
• About the influence of light on electrostatically charged bodies . In: Annalen der Physik, Vol. 33, 1888, pp. 301-312.
• About the electrification of metal plates by irradiation with electr. Light . In: Annalen der Physik, Vol. 34, 1888, pp. 731-734.
• About the connection between the loss of electricity through illumination and the absorption of light . In: Annalen der Physik, Vol. 37, 1889, pp. 666-675
• The photoelectricity . Leipzig 1914.

literature

• Armin Hermann:  Hallwax, Wilhelm. In: New German Biography (NDB). Volume 7, Duncker & Humblot, Berlin 1966, ISBN 3-428-00188-5 , p. 565 f. ( Digitized version ).

swell

Catalog of professors in the university archive of the Technical University of Dresden

Web links

• Peter Paufler: Hallwax, Wilhelm Ludwig Franz . In: Institute for Saxon History and Folklore (Ed.): Saxon Biography .
• Overview of the courses of Wilhelm Hallwachs (physicist) at the University of Leipzig (summer semester 1887 to summer semester 1888)
• Hallwachs, Wilhelm Ludwig Franz in the Hessian biography