GERHARDT, KARL FRIEDRICH, an eminent chemist, was b. at Strasburg on Aug. 21, 1816, and d. in that city on Aug. 19, 1856. At the age of 15, lie was sent to the Polytechnic school at carlsrnhe, where his attendance at prof. Walchner's lectures first • awaked in his mind a taste for chemistry. After two years' residence in this town lie removed to Leipsic, where he attended the lectures of Erdmann, which seem to have developed in him an irresistable passion for questions of speCulative chemistry.
On his return home, lie reluctantly entered upon the business of his father, who was a manufacturer of chemical products; but the requirements of commerce seem to have been intensely repugnant to him, and in a hasty moment of passion he enlisted (being, now in his twentieth year) in a regiment of chasseurs. He soon, however, found a military life as insupportable as a commercial career, and in the course of three months he purchased his discharge, and at once set out for the laboratory of Giessen, where he worked.under Liebig's superintendence for 18 months. In 1838, be arrived in Paris, , where he was cordially welcomed by Dumas. Here lie gave lectures and instructions in chemistry, and, with Chevreul's permission, worked in the laboratory of the Jardin des Plantes, where, in association with his friend Cahours (to whose memoir of Ger hardt, we are indebted for many of the facts noticed in this article), lie commences his important researches on the essential oils. In 1844, lie was appointed professor of general chemistry in the faculty of sciences at Montpelier, and in the same year he mar ried the youngest daughter of the late Dr. James Sanders of Edinburgh. About this
time he published his Precis de Chinrie Organique, in which he sketches the idea of " Homologous and Hetetologous Series" (q.v.), which at a later period he so success fully developed. In 1845, in association with Laurent, he commenced the ,Comptes ren des des Travaux de Plied e pvblies en France et a rEeranger, which were continued till 1848. In 1848, he resigned his chair and returnee] to Paris, in order to follow out uninterruptedly his special investigations;,and in that city-he established, between the years 1849 and 1855, in successive memoirs, his views of series (already adverted to) and the theory of types, with which his name will be ever associated in the history of chem istry. It was there, also, that he gave to the scientific world his remarkable researches upon the anhydrous acids and the oxides. All his ideas and his discoveries are embod ied in his Traite de China& Organique (1833-56, 4 vols.), which forms, to use the words of his friend and biographer Cahours, " an important monument of modern science." He had hardly completed the correction of the last proof of this great work, when, after au illness of only two days, he was surprised by the hand of death at the very period when he seemed to be beginning to enjoy the fruit of his labors; for lie had just received the diploma of corresponding member of the academy of sciences at Paris, and in the previous year he was appointed professor of chemistry at Strasburg.