Lewis Feuchtwanger (11 January 1805 Fürth, Kingdom of Bavaria – 25 June 1876 New York City) was a German-born chemist known primarily for his work on United States coinage.
Lewis Feuchtwanger was the son of a mineralogist, and inherited a taste for natural science, to which he devoted special attention at the University of Jena.
After receiving his doctor of philosophy degree there in 1827, he emigrated to the United States in 1829, and settled in New York, where he opened the first German pharmacy, and also practiced medicine, being particularly active during the cholera epidemic of 1832.
Subsequently, he devoted his entire attention to chemistry and mineralogy, and became engaged in the manufacture and sale of rare chemicals.
After the great fire of 1846 he called the attention of the authorities of New York to the fact that saltpetre would explode under certain conditions.