During the Middle Ages a number of crafts involving the use of chemical processes and a certain chemical knowledge were practiced by Jews. Jews sometimes dabbled in *alchemy, which frequently led to results of importance to chemistry; the responsa of the geonim mention merchants of Egypt who were attracted to alchemy. Prominent among the crafts involving chemistry were *dyeing and soapmaking, in which Jews specialized in various countries at different periods. The Jews of Tunisia exported soap in large quantities, on occasions involving hundreds of pounds in weight, to Egypt in the 11th and 12th centuries. Soap would sometimes be brought also from Ereẓ Israel and Syria; the fluctuation in prices coinciding with the arrival of ships from Tunisia is marked. A workshop for soap production was built by a Jew in Marseilles in the 14th century, and there were Jewish producers of soap at Arles and Genoa at that time. In 1381, a Jew in Majorca was granted a monopoly on the soap industry for ten years. In 1594–95 the Jews of Leghorn established two soap factories. Throughout the 16th century the finest quality soap, mainly from olive oil, was produced by Jews in the Ottoman Empire. Occasionally they used animal fat, even pig fat, for the handling of which they received special permission from the rabbis of Salonika. In 1515 it was reported that some Jews of Rome had invented an improved process for the manufacture of potassium nitrate (saltpeter), the principal ingredient in the manufacture of gunpowder. In 1630 a Levantine merchant named Naḥman Judah was permitted to manufacture cinnabar, sublimates and other chemical compounds in Venice, and even to live outside the ghetto for this purpose. After his death a similar privilege was granted to another Jew for the manufacture of these materials as well as aqua fortis and white lead.
Jewish scientists and industrialists have been prominent in modern chemical science and industry. However, despite individual enterprise and achievement, the proportion of Jews engaged in this branch has been small even in comparison with their participation in other industries. The 266 Jews employed in the chemical industries in Germany in 1882 formed 1% of the total number of Jews employed in German industries at that date. The number increased to 1,693 in 1925 but still formed only 3.43% of the total number of Jews employed in German industries. In Poland, 8,139 Jews were employed in chemical industries in 1931, forming 1.6% of the total number of Jews employed in Polish industries, compared with 2.5% for non-Jews. Notable individual contributions were made by Jews to chemistry in Poland in the 19th century, since this was a rapidly developing field which depended on scientific ability and skilled management and was relatively unhampered by old traditions. In the period between the two world wars Jews were the leading producers of soap, candles, and cosmetics in Poland. The sole factory for aniline dyes there was established by a Jew. The PPG factory for rubber products was founded by Jews.
Notable among the pioneers of the chemical industry in Germany were C.T. *Liebermann, in the production of dyes from synthetics; Heinrich *Caro, manager of the Badische Anilin-und Sodafabrik, who invented a number of synthetic dyes including red dye from aniline; Adolf von *Baeyer, inventor of a method for the production of indigo blue from intro-phenylpropiole acid; and the brothers Arthur and Carl Weinberg, who worked for Leopold Casella and Company on dye production, and subsequently for the I.G. Farben company. The first potash plant in Germany was established by Adolph Frank in 1861. Nikodem *Caro assisted him in developing the fixing of nitrogen and headed the Bayerische Stickstoffwerke in Munich. Fritz *Haber, the leading chemist of his era, saved the German munition industry in World War I by his timely discovery of a process for synthesizing ammonia. In England, important contributions were made by Ludwig *Mond and his son Alfred (Lord *Melchett). Ludwig, with his partner and assistant J. Brunner, established a soda factory in 1873 in Winnington and in 1880 founded the firm Brunner, Mond and Co. which became the leading alkali producers. He revolutionized the chemical industry with the discovery of a new method for the extraction of sulfur from by-products of alkalis; he also invented the famous mondgas and discovered the nickel carbonyl process. Alfred later became head of the firm and of the International Nickel Co. Ltd. and headed the Imperial Chemical Industries. Numerous Jews have founded or directed undertakings in the chemical industries in the United States, including H. Bennett, manager of Glyco Products Co. Inc., of New York from 1927–58; S. Cohen, chairman and manager from 1954 of Petrocarbon Chemical Inc. of Dallas, Texas; and A. Epstein (1890–1948), a leading member of Epstein, Reynolds, and Harris in Chicago. Important firms established in South Africa at the end of the 19th century include the Jewish-owned Schlesinger-Delmore soap factory in Cape Town, a match factory founded by F. Ginsberg in 1886 in King Williams Town, and a soap and candle factory also founded there by Ginsberg in 1890.
S.D. Goitein, A Mediterranean Society, 1 (1967), index; L. Gershenfeld, The Jew in Science (1934), 133–8; C. Roth, Jewish Contribution to Civilization (19563), 153–6; S. Kaznelson (ed.), Juden im deutschen Kulturbereich (19623), 777–81; J. Lestschinsky, Goralah ha-Kalkali shel Yahadut Germanyah (1963), 89–90; M. Wischnitzer, History of Jewish Crafts and Guilds (1965), 86, 102, 133; E. Fraenkel, in: F. Boehm and W. Dirks (ed.), Judentum, 2 (1965), 596; R. Mahler, Yehudei Polin bein Shetei Milḥamot Olam (1968), 72, 75ff., 81ff., 87, 95, 97ff.; 106, 108ff.; N. Shapira, in: Gesher, 5 (1959), 68ff.; L. Slesinger, in: MGWJ, 82 (1938), 111–30, 417–22.