Editing Fritz Haber (section)

==Between World Wars==
From 1919 to 1923 Haber continued to be involved in Germany's secret development of chemical weapons, working with [[Hugo Stoltzenberg]], and helping both Spain and Russia in the development of chemical gases.<ref name=Stoltzenberg />{{rp|169}}

During the 1920s, scientists working at Haber's institute developed the [[hydrogen cyanide|cyanide]] gas formulation [[Methyl cyanoformate|Zyklon A]], which was used as an [[insecticide]], especially as a [[fumigation|fumigant]] in grain stores.<ref>{{cite journal | author=Szöllösi-Janze, M. | title=Pesticides and war: the case of Fritz Haber | journal=European Review | year=2001 | volume=9 | issue=1 | pages=97–108 | doi=10.1017/S1062798701000096 | s2cid=145487024 }}</ref>

From 1919 to 1925, in response to a request made by German ambassador [[Wilhelm Solf]] to Japan for Japanese support for German scholars in times of financial hardship, a Japanese businessman named Hoshi Hajime, the president of Hoshi Pharmaceutical Company, donated two million Reichsmark to the [[Kaiser Wilhelm Society]] as the 'Japan Fund' (Hoshi-Ausschuss). Haber was asked to manage the fund, and was invited by Hoshi to Japan in 1924. Haber offered a number of chemical licences to Hoshi's company, but the offers were refused. The money from the Fund was used to support the work of [[Richard Willstätter]], [[Max Planck]], [[Otto Hahn]], [[Leo Szilard]], and others.<ref>{{cite book |last1=Sprang |first1=Christian |last2=Kato |first2=Tetsuro |title=Japanese-German Relations 1895–1945 |date=2006 |publisher=Routledge |isbn=041545705X |page=127}}</ref>

In the 1920s, Haber searched exhaustively for a method to extract gold from sea water, and published a number of scientific papers on the subject. After years of research, he concluded that the concentration of gold dissolved in sea water was much lower than that reported by earlier researchers, and that gold extraction from sea water was uneconomic.<ref name="Goran">{{cite book | last=Goran | first=Morris | title=The Story of Fritz Haber | publisher=University of Oklahoma Press | year=1967 | isbn=978-0-8061-0756-1 | url=https://books.google.com/books?id=im24AAAAIAAJ | access-date=30 April 2021 | archive-date=23 February 2024 | archive-url=https://web.archive.org/web/20240223090223/https://books.google.com/books?id=im24AAAAIAAJ | url-status=live }}</ref>{{rp|91–98}}

By 1931, Haber was increasingly concerned about the rise of [[National Socialism]] in Germany, and the possible safety of his friends, associates, and family. Under the [[Law for the Restoration of the Professional Civil Service]] of 7 April 1933, Jewish scientists at the [[Kaiser Wilhelm Society]] were particularly targeted. The {{Lang|de|Zeitschrift für die gesamte Naturwissenschaft}} ("Journal for all natural sciences") charged that "The founding of the Kaiser Wilhelm Institutes in Dahlem was the prelude to an influx of Jews into the physical sciences. The directorship of the Kaiser Wilhelm Institute for Physical and Electrochemistry was given to the Jew, F. Haber, the nephew of the big-time Jewish profiteer Koppel". (Koppel was not actually related to Haber.)<ref name=Stoltzenberg />{{rp|277–280}} Haber was stunned by these developments, since he assumed that his conversion to Christianity and his services to the state during World War I should have made him a German patriot.{{sfn|Hager|2008|p=235–236}} Ordered to dismiss all Jewish personnel, Haber attempted to delay their departures long enough to find them somewhere to go.<ref name=Stoltzenberg />{{rp|285–286}} As of 30 April 1933, Haber wrote to [[Bernhard Rust]], the national and Prussian minister of Education, and to [[Max Planck]], president of the Kaiser Wilhelm Society, to tender his resignation as the director of the Kaiser Wilhelm Institute, and as a professor at the university, effective 1 October 1933. He said that although as a converted Jew he might be legally entitled to remain in his position, he no longer wished to do so.<ref name=Stoltzenberg />{{rp|280}}

Haber and his son Hermann also urged that Haber's children by Charlotte Nathan, at boarding school in Germany, should leave the country.<ref name=Stoltzenberg />{{rp|181}} Charlotte and the children moved to the United Kingdom around 1933 or 1934. After the war, Charlotte's children became British citizens.<ref name=Stoltzenberg />{{rp|188–189}}