GERHARDT, CHARLES FREDERIC French chemist, was born at Strasbourg on Aug. 21, 1816. After attending the gymnasium at Strasbourg and the polytechnic at Karlsruhe, he was sent to the school of commerce at Leipzig, where he studied chemistry under Otto Erdmann. Later he worked for some time with Liebig at Giessen and became professor of chemistry at Montpellier in 1844, and in 1855 at Strasbourg, where he died on Aug. 19, 1856. Although Gerhardt did some noteworthy experimental work—for instance, his preparation of acid anhydrides in 1852—his contributions to chemistry consist not so much in the discovery of new facts as in the introduction of new ideas that vitalized and organized an inert accumulation of old facts. In 1839 he revived the old radicle theory of organic compounds under the title of the "theory of residues." He first suggested that many organic substances were "conjugated" or "copulated" compounds formed by the union of two residues. In 1842 he attempted the first definite classification of organic com pounds, but owing to the obscurity of some of his concepts, little progress was made until he co-operated with Laurent (q.v.). Eventually Gerhardt introduced the idea that all substances were based on four main types; viz., hydrogen, hydrochloric acid, water and ammonia. Although these ideas were later abandoned they play an important part in the development of structural organic chemistry (see CHEMISTRY : Organic) .
His chief works were Precis de chimie organique , and Traite de chimie organique (1853-56).
See Charles Gerhardt, sa vie, son oeuvre, sa correspondance, by his son, Charles Gerhardt, and E. Grimaux (Paris, 19oo) .