Leonard Ornstein

Leonard Ornstein (1927)

Leonard Salomon Ornstein (born November 12, 1880 in Nijmegen , † May 20, 1941 in Utrecht ) was a Dutch physicist.

Live and act

Leonard Salomon was the only son of the businessman Nathan Leonard Ornstein (born April 20, 1835 in Nijmegen; † October 2, 1916 in The Hague) and his wife Sophia Maria Manson (born February 14, 1846 in The Hague; † April 11, 1922 in Utrecht). He had passed through the higher civil schools in Nijmegen and The Hague . After completing his university entrance qualification, he began studying theoretical physics at the University of Leiden in 1898 . Here Hendrik Antoon Lorentz became his formative teacher. On March 26, 1908 he did his doctorate under Lorentz with the topic Toepassing the statistical mechanica van Gibbs op molekulair-theoretical vraagstukken , on the molecular applications of the Gibbs statistical mechanics to the doctor of the natural sciences. He then became Lorentz's assistant and in 1909 went to the University of Groningen as a lecturer in physics , which task he took on on April 29, 1909 with the introductory lecture De rol der wiskunde in de mathematische physica (German: The role of mathematics in mathematical physics ) .

In 1914 he succeeded Peter Debye as professor of physics at the University of Utrecht . As head of the physics laboratory in Utrecht from 1922, he also turned to experimental investigations there, in particular intensity measurements of spectral lines, and thus gave the institute an international reputation. In 1921 he was significantly involved with the director of the Philips Natuurkundig Laboratorium in Eindhoven Gilles Holst in the establishment of the Dutch Physical Society (Nederlandse Natuurkundige Vereniging), of which he was chairman in 1939/1940. In 1931/32 he was rector of the University of Utrecht , for which he gave the rector's speech De beteekenis der natuurkunde voor cultuur en maatschappij (German: The meaning of physics for culture and society ) in 1932 . Ornstein became a member of the Royal Dutch Academy of Sciences, corresponding honorary member of the Royal Physiographical Society in Lund and Knight of the Order of the Dutch Lion .

After the German occupation in 1940, as a Jew who was also active in the Zionist movement (from 1918 to 1922 he was chairman of the Dutch Zionist Association), he was in great danger, but refused to leave the country despite offers from friends. Like all Jews in the Netherlands, he was removed from public office and was even banned from entering his laboratory in Utrecht. Ornstein then isolated himself from the public and died a little later. His body was buried on May 23, 1941 in the Jewish cemetery in Utrecht.

Ornstein is best known for his work in statistical mechanics. The Ornstein-Uhlenbeck process (Ornstein, Uhlenbeck On the theory of Brownian Motion , Physical Review Vol. 36, 1930, p. 823) is named after him and George Uhlenbeck . The Ornstein-Zernike theory (1914, with Frits Zernike ) determines the spatial correlation function of, for example, molecules in liquids self-consistently using an integral equation .

A laboratory at the University of Utrecht is named after him in his honor.

family

Ornstein was married twice. His first marriage was on June 29, 1911 in Amsterdam with Jeanette Hoofien (* February 2, 1886 in Utrecht; † September 22, 1948 in Israel), the daughter of Jacob Hoofien (* approx. 1847 Steenwijk;) and Rozina Blaauw (* June 30, 1855 in Utrecht, † March 14, 1911 in Amsterdam). There are two daughters from the marriage. After his divorce on March 24, 1927, Ornstein married Sophia Estella Meijer (born November 12, 1902 in Werkendam; † February 9, 1987 in Velp), the daughter of Maurit Jacob Meijer (born August 17, 1987 in Utrecht) on March 8, 1929 1873 in Werkendam; † February 26, 1943 in Oswiecim (Poland)) and the Mietje Marsman (born June 17, 1872 in Leiden; † February 26, 1943 in Oswiecim (Poland)). There are two sons from the marriage. From the children we know:

• Hadassa Ornstein (born March 13, 1917 Utrecht, † 1978 Tel Aviv) m. Baumann
• Daughter NN. Ornstein (* & † June 24, 1918 in Utrecht)
• Rachel Sippora Ornstein (born August 29, 1919 in Utrecht) married. Binjamin Soloveitchik (born December 12, 1913 Dnipropetrovsk, † August 5, 1977 in Tel Aviv)
• Lodewijk Theodoor Manne Ornstein (born February 26, 1931 Utrecht, † December 7, 1997 ibid) m. I. March 2, 1955 in Amsterdam with Henriette Edersheim (born July 8, 1933 in Amsterdam; † September 21, 2007 in MD. USA) married. II. Eva van Slooten; The grandson Leonard Salomon Ornstein (born August 21, 1955 in Amsterdam), who made a name for himself as a journalist, comes from his first marriage
• Mathijs Alexander Manne Ornstein (born February 4, 1933 in Utrecht; † April 2, 2005) married. January 11, 1964 in Amersfoort with Anna Elisabeth Lambrechtsen (born March 25, 1936 in Maartensdijk)

Works (selection)

• Toepassing the statistical mechanica van Gibbs opolekulair-theoretical vraagstukken . IJdo, Leiden, 1908
• De rol der wiskunde in de mathematische physica. van Doesburgh, Leiden 1909
• Problems of the kinetic theory of van de stof. Oosthoek, Utrecht, 1915
• Objective spectrophotometry. Vierweg, Braunschweig, 1932 (with Willem Jan Henri Moll and Herman Carel Burger)
• De beteekenis der natuurkunde voor cultuur en maatschappij. Utrecht, 1932
• Radiation law and intensity of multiple lines. 1924
• Intensity of the components in the Zeeman effect. 1924
• On the theory of the Brownian motion. 1930
• De beteekenis der natuurkunde voor cultuur en maatschappij. Utrecht 1932
• Daylight measurements in Utrecht. Amsterdam 1936

literature

• N. Japinske: Persoonlijkheden in het Koninkrijk der Nederlanden in woord en beeld. Van Holkema & Warendorf NV, Amsterdam, 1938, p. 1111 ( online )
• H .A. Kramers: Levens report LS Ornstein. In: Jaarboek Koninklijke Nederlandse Akademie van Wetenschappen, 1940-1941. Amsterdam, 1941, pp. 225-231 ( Online PDF )
• HAM Snelders: Ornstein, Leonard Salomon (1880-1941). In: Biographical Woordenboek van Nederland. The Hague, 1985, Vol. 2, ( Online )

Web links

• Ornstein entry at the Royal Dutch Academy of Sciences (KNAW)
• Ornstein entry in the Catalogus Professorum Academiae Rheno-Traiectinae