Editing Olry Terquem

{{short description|French mathematician}}
{{For|the French pharmacist and paleontologist|Olry Terquem (paleontologist)}}
{{Infobox writer
| name = Olry Terquem
| birth_date = 16 June 1782
| birth_place = [[Metz]], [[France]]
| death_date = 6 May 1862  (aged 79)
| death_place = [[Paris]], [[France]]
| occupation = [[mathematician]], [[geometry]]
| alma_mater = 
}}

'''Olry Terquem''' (16 June 1782 – 6 May 1862) was a [[French people|French]] [[mathematician]]. He is known for his works in [[geometry]] and for founding two [[scientific journal]]s, one of which was the first journal about the [[history of mathematics]]. He was also the [[pseudonym]]ous author (as '''Tsarphati''') of a sequence of letters advocating radical reform in Judaism.<ref name="je">{{citation|contribution=Terquem, Olry|title=[[Jewish Encyclopedia]]|year=1906|publisher=Funk and Wagnalls|contribution-url=http://www.jewishencyclopedia.com/articles/14337-terquem-olry}}.</ref> He was [[History of the Jews in France|French Jewish]].

==Education and career==
Terquem grew up speaking [[Yiddish]], and studying only the [[Hebrew language]] and the [[Talmud]].<ref name="waterhouse">{{citation
 | last = Waterhouse | first = William C. | authorlink = William C. Waterhouse
 | doi = 10.2307/2975573
 | issue = 6
 | journal = The American Mathematical Monthly
 | mr = 707152
 | pages = 378–387
 | title = Do symmetric problems have symmetric solutions?
 | url = http://www.maa.org/sites/default/files/pdf/upload_library/22/Ford/Waterhouse378-387.pdf
 | volume = 90
 | year = 1983| jstor = 2975573 }}. Biographical appendix, pp. 385–386.</ref> However, after the [[French Revolution]] his family came into contact with a wider society, and his studies broadened.<ref name="waterhouse"/> Despite his poor French he was admitted to study mathematics at the [[École Polytechnique]] in Paris, beginning in 1801, as only the second Jew to study there.<ref name="je"/><ref name="waterhouse"/><ref name="ratcliffe">{{citation|title=Mathematics and Social Utopias in France: Olinde Rodrigues and His Times|volume=28|series=History of Mathematics|editor1-first=Simon|editor1-last=Altmann|editor2-first=Eduardo L.|editor2-last=Ortiz|publisher=American Mathematical Society|year=2006|isbn=9780821842539|contribution=Chapter 3. Towards a better understanding of Olinde Rodriguez and his circle: family and faith in his life and career|first=Barrie M.|last=Ratcliffe|pages=39–70}}. See in particular [https://books.google.com/books?id=o8hCH7R7TjMC&pg=PA60 pp.&nbsp;60–61].</ref> He became an assistant there in 1803, and earned his doctorate in 1804.

After finishing his studies he moved to [[Mainz]] (at that time known as Mayence and part of imperial France), where he taught at the Imperial Lycée. In 1811 he moved to the [[School of Applied Artillery (France)|artillery school]] in the same city, in 1814 he moved again to the artillery school in [[Grenoble]], and in 1815 he became the librarian of the Dépôt Central de l'Artillerie in Paris, where he remained for the rest of his life. He became an officer of the [[Legion of Honor]] in 1852. After he died, his funeral was officiated by [[Lazare Isidor]], the [[Chief Rabbi]] of Paris and later of France, and attended by over 12 generals headed by [[Edmond Le Bœuf]].<ref name="je"/><ref name="waterhouse"/>

==Mathematics==
Terquem translated works concerning [[artillery]], was the author of several textbooks, and became an expert on the history of mathematics.<ref name="waterhouse"/> Terquem and [[Camille-Christophe Gerono]] were the founding editors of the ''[[Nouvelles Annales de Mathématiques]]'' in 1842.<ref name="je"/> Terquem also founded another journal in 1855, the ''Bulletin de Bibliographie, d'Histoire et de Biographie de Mathématiques'', which was published as a supplement to the ''Nouvelles Annales'', and he continued editing it until 1861.<ref name="je"/><ref name="hm"/> This was the first journal dedicated to the history of mathematics.<ref name="hm">{{citation
 | last = Dauben | first = Joseph W.
 | doi = 10.1006/hmat.1999.2227
 | issue = 1
 | journal = Historia Mathematica
 | mr = 1677459
 | pages = 1–28
 | title = Historia Mathematica: 25 years/context and content
 | volume = 26
 | year = 1999| doi-access = free
 }}.</ref>

[[File:Triangle.NinePointCircle.svg|240px|thumb|The nine-point circle of a triangle. The three marked points that lie on the circle and interior to the triangle are the ones found by Terquem. The point of convergence of the three red lines through the triangle is its [[orthocenter]].]]
In [[geometry]], Terquem is known for naming the [[nine-point circle]] and fully proving its properties. This is a [[circle]] that passes through nine special points of any given triangle. [[Karl Wilhelm Feuerbach]] had previously observed that the three [[Orthic triangle|feet of the altitudes]] of a triangle and the three [[Medial triangle|midpoints of its sides]] all lie on a single circle, but Terquem was the first to prove that this circle also contains the midpoints of the [[line segment]]s connecting each vertex to the [[orthocenter]] of the triangle.<ref>{{citation|title=Beautiful Geometry|first1=Eli|last1=Maor|first2=Eugen|last2=Jost|publisher=Princeton University Press|year=2014|isbn=9781400848331|page=140|url=https://books.google.com/books?id=0fOKAQAAQBAJ&pg=PA140}}.</ref> He also gave a new proof of Feuerbach's theorem that the nine-point circle is [[Incircle and excircles of a triangle|tangent]] to the [[incircle and excircles of a triangle]].<ref name="ratcliffe"/>

Terquem's other contributions to mathematics include naming the [[pedal curve]] of another curve,<ref name="ratcliffe"/> and counting the number of [[perpendicular line]]s from a point to an [[algebraic curve]] as a function of the degree of the curve.<ref name="waterhouse"/> He was also the first to observe that the minimum or maximum value of a [[symmetric function]] is often obtained by setting all variables equal to each other.<ref name="waterhouse"/>

==Jewish activism==
Terquem has been called the first, most radical, and most outspoken of the major proponents of Jewish reform in France,<ref name="meyer">{{citation|title=Response to Modernity: A History of the Reform Movement in Judaism|first=Michael A.|last=Meyer|publisher=Wayne State University Press|year=1995|isbn=9780814337554|pages=165–167|url=https://books.google.com/books?id=M12toEjI5PEC&pg=PA165}}.</ref><ref name="glick">{{citation|title=Marked in Your Flesh: Circumcision from Ancient Judea to Modern America|first=Leonard B.|last=Glick|publisher=Oxford University Press|year=2005|isbn=9780198039259|pages=137–138|url=https://books.google.com/books?id=SF6fbjNe0yYC&pg=PA137}}.</ref> "the ''enfant terrible'' of French Judaism".<ref name="meyer"/> He published 27 "letters of an Israelite" under the name "[[Sarfati|Tsarphati]]" (a Hebrew word for a Frenchman),<ref name="glick"/><ref name="albert">{{citation|title=Essays in Modern Jewish History: A Tribute to Ben Halpern|series=Herzl Press publications|editor1-first=Phyllis Cohen|editor1-last=Albert|editor2-first=Frances|editor2-last=Malino|publisher=Fairleigh Dickinson University Press|year=1982|isbn=9780838630952|contribution=Nonorthodox attitudes in nineteenth-century French Judaism|first=Phyllis Cohen|last=Albert|pages=121–141}}. See in particular [https://books.google.com/books?id=F8xaoJ2Xy0sC&pg=PA123 p.&nbsp;123].</ref> pushing for reforms that in his view would better assimilate Jews into modern life<ref name="glick"/> and better accommodate working-class Jews.<ref name="meyer"/> The first nine of these appeared in ''L'Israélite Français'', and the remaining 18 as letters to the editor in ''Courrier de la Moselle''.<ref>{{citation|title=Rites and Passages: The Beginnings of Modern Jewish Culture in France, 1650–1860|series=Jewish Culture and Contexts|first=Jay R.|last=Berkovitz|publisher=University of Pennsylvania Press|year=2011|isbn=9780812200157|page=282|url=https://books.google.com/books?id=CXTGK5ZRswwC&pg=PA282}}.</ref> Terquem rejected the [[Talmud]],<ref name="albert"/><ref name="hyman">{{citation|title=The Jews of Modern France|volume=1|series=Jewish communities in the modern world|first=Paula|last=Hyman|publisher=University of California Press|year=1998|isbn=9780520919297|page=72|url=https://books.google.com/books?id=7vK-yH_0gSgC&pg=PA72}}.</ref> proposed to codify intermarriage between Jews and non-Jews,<ref name="albert"/> pushed to move the [[sabbath]] to Sunday,<ref name="meyer"/><ref name="hyman"/> advocated using other languages than Hebrew for prayers,<ref name="waterhouse"/> and fought against [[circumcision]],<ref name="glick"/> regressive attitudes towards women,<ref name="meyer"/> and the [[Jewish calendar]].<ref name="meyer"/> However, he had little effect on the Jewish practices of the time.<ref name="glick"/><ref name="hyman"/>

Despite Terquem's calls for reform, and despite having married a Catholic woman and raised his children as Catholic,<ref name="meyer"/> he requested that his funeral be held with all the proper Jewish rites.<ref name="je"/>

==References==
{{reflist}}

{{Authority control}}

{{DEFAULTSORT:Terquem, Olry}}
[[Category:1782 births]]
[[Category:1862 deaths]]
[[Category:19th-century French mathematicians]]
[[Category:18th-century French Jews]]
[[Category:Geometers]]
[[Category:French historians of mathematics]]
[[Category:Officers of the Legion of Honour]]
[[Category:French librarians]]