Leonard Salomon Ornstein (12 November 1880 in

Nijmegen Nijmegen ( , ; Nijmeegs: ) is the largest city in the Dutch province of Gelderland and the ninth largest of the Netherlands as a whole. Located on the Waal River close to the German border, Nijmegen is one of the oldest cities in the ...

, the

Netherlands , Terminology of the Low Countries, informally Holland, is a country in Northwestern Europe, with Caribbean Netherlands, overseas territories in the Caribbean. It is the largest of the four constituent countries of the Kingdom of the Nether ...

– 20 May 1941 in

Utrecht Utrecht ( ; ; ) is the List of cities in the Netherlands by province, fourth-largest city of the Netherlands, as well as the capital and the most populous city of the Provinces of the Netherlands, province of Utrecht (province), Utrecht. The ...

, the Netherlands) was a Dutch

physicist A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate cau ...

Biography

Ornstein studied theoretical physics with

Hendrik Antoon Lorentz Hendrik Antoon Lorentz ( ; ; 18 July 1853 – 4 February 1928) was a Dutch theoretical physicist who shared the 1902 Nobel Prize in Physics with Pieter Zeeman for their discovery and theoretical explanation of the Zeeman effect. He derived ...

at the

University of Leiden Leiden University (abbreviated as ''LEI''; ) is a public research university in Leiden, Netherlands. Established in 1575 by William, Prince of Orange as a Protestant institution, it holds the distinction of being the oldest university in the Neth ...

. He subsequently carried out Ph.D. research under the supervision of

Lorentz Lorentz is a name derived from the Roman surname, Laurentius, which means "from Laurentum". It is the German form of Laurence. Notable people with the name include: Given name * Lorentz Aspen (born 1978), Norwegian heavy metal pianist and keyboar ...

, concerning an application of the

statistical mechanics In physics, statistical mechanics is a mathematical framework that applies statistical methods and probability theory to large assemblies of microscopic entities. Sometimes called statistical physics or statistical thermodynamics, its applicati ...

Gibbs Gibbs or GIBBS is a surname and acronym. It may refer to: People * Gibbs (surname) Places * Gibbs (crater), on the Moon * Gibbs, Missouri, US * Gibbs, Tennessee, US * Gibbs Island (South Shetland Islands), Antarctica * 2937 Gibbs, an asteroid ...

to molecular problems. In 1914, Ornstein was appointed professor of physics, as successor of

Peter Debye Peter Joseph William Debye ( ; born Petrus Josephus Wilhelmus Debije, ; March 24, 1884 – November 2, 1966) was a Dutch-American physicist and physical chemist, and Nobel laureate in Chemistry. Biography Early life Born in Maastricht, Neth ...

, at the

University of Utrecht Utrecht University (UU; , formerly ''Rijksuniversiteit Utrecht'') is a public research university in Utrecht, Netherlands. Established , it is one of the oldest universities in the Netherlands. In 2023, it had an enrollment of 39,769 students, a ...

. Among his doctoral students was

Jan Frederik Schouten Jan Frederik Schouten (29 May 1910 – 12 August 1980) was a Dutch physicist, and Professor at the Eindhoven University of Technology, known for his contributions to biophysics. H. BoumaLevensbericht J.F. Schouten in: ''Jaarboek, 1980'', Amsterdam ...

. In 1922, Ornstein became director of the Physical Laboratory (''Fysisch Laboratorium'') and extended his research interests to experimental subjects. His precision measurements concerning intensities of spectral lines brought the Physical Laboratory in the international limelight. Ornstein is also remembered for the Ornstein-Zernike theory (named after himself and Frederik Zernike) concerning correlation functions, and the Ornstein-Uhlenbeck process (named after Ornstein and

George Uhlenbeck George Eugene Uhlenbeck (December 6, 1900 – October 31, 1988) was a Dutch-American theoretical physicist, known for his significant contributions to quantum mechanics and statistical mechanics. He co-developed the concept of electron spin, alo ...

), a

stochastic process In probability theory and related fields, a stochastic () or random process is a mathematical object usually defined as a family of random variables in a probability space, where the index of the family often has the interpretation of time. Sto ...

. Together with

Gilles Holst Gilles Holst (20 March 1886 – 11 October 1968) was a Dutch physicist, known worldwide for his invention of the low-pressure sodium lamp in 1932. Early life His father was a manager of a shipyard. In 1904 he went to ETH Zurich to study mechani ...

, director of the Philips Physics Laboratory (''Philips Natuurkundig Laboratorium''), Ornstein was the driving force behind establishing the

Netherlands Physical Society The Netherlands Physical Society (, NNV) is the professional society of physicists in the Netherlands and a member of the European Physical Society. Established in 1921, the goals of the society are to promote physics and to serve the interests ...

(''Nederlandse Natuurkundige Vereniging'', NNV) in 1921. From 1939 until November 1940, he was chairman of this society. From 1918 until 1922, he was chairman of the Dutch Zionist Society (''Nederlandse Zionistische Vereniging''). In 1929, he became a member of the

Royal Netherlands Academy of Arts and Sciences The Royal Netherlands Academy of Arts and Sciences (, KNAW) is an organization dedicated to the advancement of science and literature in the Netherlands. The academy is housed in the Trippenhuis in Amsterdam. In addition to various advisory a ...

. Immediately after the May 1940 German conquest and occupation of

the Netherlands , Terminology of the Low Countries, informally Holland, is a country in Northwestern Europe, with Caribbean Netherlands, overseas territories in the Caribbean. It is the largest of the four constituent countries of the Kingdom of the Nether ...

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

(see

Battle of the Netherlands The German invasion of the Netherlands (), otherwise known as the Battle of the Netherlands (), was a military campaign, part of Battle of France, Case Yellow (), the Nazi German invasion of the Low Countries (Belgium, Luxembourg, and the Neth ...

), a friend from the

United States of America The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 states and a federal capital district, Washington, D.C. The 48 contiguo ...

, the

astronomer An astronomer is a scientist in the field of astronomy who focuses on a specific question or field outside the scope of Earth. Astronomers observe astronomical objects, such as stars, planets, natural satellite, moons, comets and galaxy, galax ...

Peter van de Kamp Piet van de Kamp (December 26, 1901 – May 18, 1995), known as Peter van de Kamp in the United States, was a Dutch astronomer who lived in the United States most of his life. He was professor of astronomy at Swarthmore College and director of ...

, offered to bring Ornstein and his family to America. However, Ornstein did not accept this offer, since, as he put it, he would not leave his laboratory in Utrecht. The Nazis targeted Ornstein for his

Jewish Jews (, , ), or the Jewish people, are an ethnoreligious group and nation, originating from the Israelites of History of ancient Israel and Judah, ancient Israel and Judah. They also traditionally adhere to Judaism. Jewish ethnicity, rel ...

heritage and the university dismissed him in September 1940, barring him from entering his laboratory. In November 1940, the university's dismissal became official. On 29 November 1940, Ornstein withdrew his membership of the Netherlands Physical Society. During this period he increasingly distanced himself from public life, to the degree that he no longer wished to receive guests at home. Ornstein died on 20 May 1941, a year after German occupation, and six months after being barred from University. One of the five buildings of the Department of Physics at the University of Utrecht is named the Leonard S. Ornstein Laboratory in his honor.

Publications

* ''Toepassing der statistische mechanica van Gibbs op moleculair-theoretische vraagstukken'', Ph.D. thesis, 26 March 1908 * ''Problemen der kinetische theorie van de stof'', 1915 * ''Strahlungsgesetz und Intensität von Mehrfachlinien'', 1924 * ''Intensität der Komponenten im Zeemaneffekt'', 1924 * ''On the theory of the Brownian motion'', 1930 * ''De beteekenis der natuurkunde voor cultuur en maatschappij'', 1932Speech in Dutch on the significance of physics to culture/civilisation and society:

References

External links

*Snelders H.A.M. (2007-02-01).
Ornstein, Leonard Salomon (1880-1941)
, in: ''Biografisch Woordenboek van Nederland''. Retrieved on 2007-03-30. ''(in

Dutch Dutch or Nederlands commonly refers to: * Something of, from, or related to the Netherlands ** Dutch people as an ethnic group () ** Dutch nationality law, history and regulations of Dutch citizenship () ** Dutch language () * In specific terms, i ...

)''.

* {{DEFAULTSORT:Ornstein, Leonard Salomon 1880 births 1941 deaths 20th-century Dutch physicists Probability theorists Leiden University alumni Academic staff of Utrecht University Jewish Dutch scientists Members of the Royal Netherlands Academy of Arts and Sciences People from Nijmegen Statistical physicists

Biography

Publications

See also

References

External links