GMELIN, the name of several distinguished German scientists, of a Tübingen family. Johann Georg Gmelin (1674–1728), an apothecary in Tübingen, and an accomplished chemist for the times in which he lived, had three sons. The first, Johann Conrad (1702–1759), was an apothecary and surgeon in Tübingen. The second, Johann Georg (1709–1755), was appointed professor of chemistry and natural history in St Petersburg in 1731, and from 1733 to 1743 was engaged in travelling through Siberia. The fruits of his journey were Flora Sibirica (4 vols., 1749–1750) and Reisen durch Sibirien (4 vols., 1753). He ended his days as professor of medicine at Tübingen, a post to which he was appointed in 1749. The third son, Philipp Friedrich (1721–1768), was extraordinary professor of medicine at Tübingen in 1750, and in 1755 became ordinary professor of botany and chemistry. In the second generation Samuel Gottlieb (1743–1774), the son of Johann Conrad, was appointed professor of natural history at St Petersburg in 1766, and in the following year started on a journey through south Russia and the regions round the Caspian Sea. On his way back he was captured by Usmey Khan, of the Kaitak tribe, and died from the ill-treatment he suffered, on the 27th of July 1774. One of his nephews, Ferdinand Gottlob von Gmelin (1782–1848), became professor of medicine and natural history at Tübingen in 1805, and another, Christian Gottlob (1792–1860), who in 1828 was one of the first to devise a process for the artificial manufacture of ultramarine, was professor of chemistry and pharmacy in the same university. In the youngest branch of the family, Philipp Friedrich had a son, Johann Friedrich (1748–1804), who was appointed professor of medicine in Tübingen in 1772, and in 1775 accepted the chair of medicine and chemistry at Göttingen. In 1788 he published the 13th edition of Linnaeus’ Systema Naturae with many additions and alterations. His son Leopold (1788–1853), was the best-known member of the family. He studied medicine and chemistry at Göttingen, Tübingen and Vienna, and in 1813 began to lecture on chemistry at Heidelberg, where in 1814 he was appointed extraordinary, and in 1817 ordinary, professor of chemistry and medicine. He was the discoverer of potassium ferricyanide (1822), and wrote the Handbuch der Chemie (1st ed. 1817–1819, 4th ed. 1843–1855), an important work in its day, which was translated into English for the Cavendish Society by H. Watts (1815–1884) in 1848–1859. He resigned his chair in 1852, and died on the 13th of April in the following year at Heidelberg.