1 66 



NATURE 



[M. 



1918 



Revue Scientifique. The journal had a somewhat 

 chequered career ; each year saw a change of pub- 

 Usher, and it ceased to appear in the troubled 

 times of 1 85 1. He now started a school of prac- 

 tical chemistry at 29 Rue M. le Prince, where he 

 had as pupils and collaborators, amongst others, 

 Chancel, Chiozza, Pisani, and for a time August 

 Kekule. It was here, too, that he made his memor- 

 able researches on the organic anhydrides — the 

 culminating point of his experimental work. 

 Shortly before his death, in 1856, at the age of 

 forty, he was transferred to Strasburg, but beyond 

 a couple of short papers published posthumously, 

 nothing further appeared from his pen. 



It would be impossible to do adequate justice, 

 in an article of this kind, to the extraordinary 

 value of Gerhardt's labours during the twenty 

 short years of his ceaseless activity. His mind 

 was continually at work upon the basic principles 

 of theoretical chemistry, and his pen was never 

 idle in expounding them. His wealth of ideas, the 

 fruitfulness of his conceptions, his grasp, the 

 range of his knowledge, and his logic and insight 

 are simply astonishing. Much of his doctrine is 

 now so woven into the structure of .the science that 

 to recall it all would seem to the student of to-day 

 to savour of the commonplace. But what a cata- 

 logue it makes ! — the reform of the atomic weights, 

 the unification of formulae, the true conception of the 

 molecule and the atom, constitutional formulae, the 

 principleof homology, the role oi water in chemical 

 change, the basicity of acids, and the nature and 

 classification of salts. Such is the baldest summary 

 of G^hardt's influence on the philosophy of chem- 

 istry, as expounded in his critical papers and his 

 various text-books, above all in his classical 

 treatise on organic chemistry. His published 

 papers number more than 100, almost exclusively 

 on subjects of organic chemistry — essential oils, the 

 alkaloids, amides, anilides, ureides, thiocyanates, 

 mellonides, and lastly the acid anhydrides — co- 

 extensive, in fact, with the whole range of that 

 section of the science. The admirable biography 

 which we owe to M. Grimaux and the filial piety 

 of M. Charles Gerhardt, jun.*, does full justice to 

 these imperishable labours, and they are recalled 

 in graceful and felicitous terms in the Conference 

 which M. Marc Tiffeneau delivered before the 

 Chemical Society of France on the centenary of 

 the birth of their illustrious author. 



Charles Adolphe Wurtz was born at Strasburg 

 on November 26, 18 17. He was the son of a 

 Lutheran pastor in a small village near that city, 

 and it was the intention of his father, who had 

 inscribed his name at the Protestant seminary of 

 theology, that he should follow his own profession. 

 The boy, however, had been irresistibly attracted 

 towards chemistry, and his inclination was 

 strengthened by his association with Caillot, then 

 professor at Strasburg, to whom eventually be 

 became lecture-assistant. The father had little 

 sympathy with the son's aspirations. In his judg- 

 ment chemical science offered little or no prospect 

 of a living, and accordingly the young Wurtz, to 

 NO. 2531, VOL. lOl] 



meet in some degree his parent's objections, ap- 

 phed himself to medicine and took his degree in 

 that subject in 1843. In the course of his studies 

 he repaired to Giessen, then the Mecca of chemists, 

 and worked under Liebig for about a year. This 

 circumstance determined his career. In 1844 he 

 left Alsace to join Dumas, to whom he had beer* 

 recommended by Liebig, and in the well-known 

 laboratory in the Rue Cuvier he worked in com- 

 pany with Cahours, Melsens, Stas, Piria, and 

 others, who became more or less eminent in that 

 stirring and fruitful epoch. 



Dumas 's influence at that period was all-powerful 

 in France, and Wurtz's rise was rapid. He was 

 "chef des travaux chimiques " at the Ecole Cen- 

 trale in 1845, and in 1846 a member of the Faculty 

 of Medicine. When Dumas became Minister of 

 Agriculture and Commerce, after the Revolution 

 of 1848, Wurtz succeeded him as professor of 

 organic chemistry, becoming titular professor of 

 mineral chemistry in 1853 in succession to Orfila 

 and a line of such illustrious ancestors as Fourcroy 

 and Vauquelin. Here he remained for twenty-one 

 years, attracting to himself a body of active 

 workers from all parts of Europe and America 

 by his power as a teacher, and by the enthusiastic 

 energy with which he directed his school of re- 

 search. In 1872 he was made professor of organic 

 chemistry at the Sorbonne, a position created for 

 him. He retired In 1882 and died on May 12, 

 1884. 



During the half-century of Wurtz's scientific 

 activity France passed through many political 

 crises, which, no doubt, at times were not without 

 influence on his position and prospects, but, on 

 the whole, his career was far more placid and 

 prosperous than that of his brilliant compatriot. 

 Although practically contemporaries, Gerhardt was 

 at the height of his fame when Wurtz was but 

 little known outside Paris. To-day, indeed, the 

 men seem to belong to a different age. By far 

 the greater volume of Wurtz's work was published 

 when Gerhardt had ceased to write. His earliest 

 efforts were on inorganic subjects. He studied 

 the acids of phosphorus and determined their 

 basicities, which he afterwards confirmed by 

 preparing their compound ethers ; he discovered 

 phosphoryl chloride and copper hydride, the first 

 member of this class of substances to be made 

 known, and noted the significance of the mode of 

 its decomposition by hydrochloric acid in refer- 

 ence to the atomic constitution of elements in the 

 free state. 



But under the influence of Dumas he soon turned 

 into the rapidly developing field of organic chem- 

 istry. His work on copper hydride led him to 

 speculate on.the constitution of Frankland's com- 

 pound radicals, and to indicate the necessary exist- 

 ence of mixed radicals, such as methyl-ethyl, ethyl- 

 amyl, etc. He discovered liquid cyanogen chloride 

 and synthesised urethane, and prepared the cyanic 

 and cyanuric ethers and the first of the compound 

 ammonias — a subject brilliantly exploited by Hof- 

 mann a few years later. He prepared the com- 

 pound ureas, established the triatomic character of 



