│Friedrich Wöhler│ was born at Eschersheim, near Frankfort, on July 31, 1800. After studying at Marburg, where he discovered, independently of Davy, _cyanogen iodide_, and worked on _mercuric thiocyanate_, he went to Heidelberg and investigated _cyanic acid_ and its compounds, under the direction of Gmelin. In 1823 he worked with Berzelius at Stockholm, where he prepared some new tungsten compounds and practised mineral analysis. In 1825 he became a teacher of chemistry in the Berlin Trade School. Here he succeeded for the first time in preparing the metal _aluminium_ and in effecting the _synthesis of urea_—one of the first organic compounds to be prepared from inorganic materials. Jointly with Liebig he worked upon _mellitic_ and _cyanic_ and _cyanuric acids_. In 1832 Wöhler, now appointed to the Polytechnic at Cassel, began with Liebig their memorable investigation on _bitter-almond oil_. In 1836 he was called to the Chair of Chemistry in the University of Göttingen, and with Liebig attacked the constitution of _uric acid and its derivatives_—the last great investigation the friends did in common. Wöhler subsequently devoted himself mainly to inorganic chemistry. He isolated _crystalline boron_, and prepared its _nitrides_, discovered the spontaneously inflammable _silicon hydride_, _titanium nitride_, and analysed great numbers of minerals and meteorites and compounds of the rarer metals. He made Göttingen famous as a school of chemistry. At the time of the one and twentieth year of his connection with the University it was found that upwards of 8000 students had listened to his lectures or worked in his laboratory. He died on September 23, 1882. In France, Dumas exercised a no less powerful influence. If Liebig could reckon among his pupils Redtenbacher, Bromeis, Varrentrapp, Gregory, Playfair, Williamson, Gilbert, Brodie, Anderson, Gladstone, Hofmann, Will, and Fresenius; Dumas could point to Boullay, Piria, Stas, Melsens, Wurtz, and Leblanc—all of whom did yeoman service in developing the rapidly expanding branch of organic chemistry. [Illustration: JEAN BAPTISTE ANDRÉ DUMAS]