June 19, 1884] 



NA TURE 



171 



attached ; of these a large proportion recite particulars of 

 researches which have furnished results of high theoretical 

 importance, and which entitle their author to be reckoned 

 as one of the chief contributors to the foundation of sys- 

 tematic chemistry. In him French chemists lose their 

 chief leader ; but their loss is also that of the scientific 

 world at large. His logical clearness of thought, his 

 breadth of view, and the precision of his statements 

 secured Wurtz an influence wherever chemistry was 

 taught ; and at the present time, overwhelmed as we are 

 in the chaos of facts brought to light with such astound- 

 ing rapidity by the labours of chemists in all parts of the 

 world, the loss of such a master-mind, of a man possessed 

 in so high a degree of the power of coordination, is 

 indeed grievous. His " Introduction to Chemical Philo- 

 sophy," his " History of Chemical Theory," and his 

 "Atomic Theory," of all of which English translations 

 have been published, afford striking illustrations of the 

 character of his teaching, and are unsurpassed as intro- 

 ductions to the study of the historical development of our 

 science. 



Wurtz's first paper, published in 1S42, was " On the 

 Constitution of the Hypophosphites," and, together with 

 another on the same subject put forward a year or so 

 later, forms not the least important of his contributions. 

 Hypophosphorous acid had been discovered by Dulong 

 and afterwards examined by Heinrich Rose, but their 

 results were not in accordance ; Wurtz therefore under- 

 took the study of the acid. He established its compo- 

 sition and prepared and analysed a large number of its 

 salts, and was thereby led to the conclusion that hypo- 

 phosphorous acid contained two atoms of hydrogen 

 which could not be displaced by metals, being, in fact, a 

 monobasic acid ; he also showed that of the three atoms 

 of hydrogen in phosphorous acid only two were displaced 

 in the formation of salts. This research was carried out 

 in Dumas' laboratory ; it may even now serve as a model 

 of what such work should be. 



In the course of his study of the hypophosphites, Wurtz 

 was led to make what probably was his most interesting, 

 although not his most important, discovery : that of 

 copper hydride, Cu 2 H 2 . Even at the present day, although 

 we have reason to believe that the alkali metals and pal- 

 ladium and platinum form compounds with hydrogen, 

 copper hydride is the only hydride of a metal with which 

 we are acquainted which has anything like definite and 

 specific properties. It is obtained by acting on copper 

 sulphate with hypophosphorous acid as a yellow or reddish- 

 brown precipitate, which when heated readily decomposes 

 into hydrogen and copper, and on treatment with muriatic 

 acid yields cuprous chloride and twice the volume of 

 hydrogen which is obtained on merely heating it. This 

 reaction, as Brodie first pointed out, affords an almost 

 conclusive argument for assuming that the hydrogen 

 molecule is compound in its nature. Berthelot having 

 called in question the existence of cuprous hydride, Wurtz 

 in 1880 maintained the correctness of his original state- 

 ments. It is to be hoped that this remarkable compound 

 will ere long again attract attention, as it is more than 

 probable that it will be of service as a reducing agent ; 

 its thermo-chemical investigation may be expected to 

 furnish important information on the affinity of hydrogen 

 atoms for hydrogen atoms : indeed it is remarkable that 

 it has so long escaped attention from this point of view. 



Wurtz paid much attention to the investigation of the 

 cyanogen compounds, and in studying the cyanic ethers 

 was led in 1847-49 to make the most brilliant of his dis- 

 coveries, that of the compound ammonias. These bodies 

 were obtained by the action of alkali on cyanic ethers, 

 just as ammonia is formed from cyanic acid. In properties 

 they were the precise analogues of ammonia, and on this 

 account, and on account of the manner in which they were 

 produced, Wurtz at once regarded them as ammonias in 

 which an atom of hydrogen is displaced by an alcohol 



radicle such as methyl or ethyl, thus giving rise to the 

 idea of the ammonia type. Hofmann's discovery, a few 

 months later, of diethylamine and triethylamine, com- 

 pounds resulting from the displacement of two and three 

 atoms of hydrogen in ammonia by ethyl, and of the 

 method of preparing amines by the action of the alcoholic 

 iodides on ammonia, was a fitting corollary to that of 

 Wurtz. The combined result of these two classical re- 

 searches was that chemists have ever since accounted for 

 the properties of the organic bases generally by regarding 

 them as derivatives of ammonia, which they all so closely 

 resemble in chemical behaviour. 



Passing over numerous investigations of minor value, 

 we come to a paper published in 1855, " On Simple and 

 Mixed Organic Radicles," which at that time was of great 

 importance, and well illustrates Wurtz's method of almost 

 invariably choosing subjects the investigation of which 

 was of special interest as bearing on the advance of 

 chemical theory. This paper is also memorable as con- 



Wurtz (from La Nature). 



taining the first description of the method now so com- 

 monly employed of preparing hydrocarbons by the action 

 of sodium on the iodides and bromides of alcohol radicles, 

 a method which some years afterwards was applied with 

 such success by Fittig in elucidating the constitution of 

 the homologues of benzene. Frankland and Kolbe had 

 maintained that the hydrocarbons of the empirical com- 

 position of the so-called alcohol radicles which they had 

 prepared were of the same composition in the free state 

 as in combination : for example, that the hydrocarbon 

 obtained from ethyl iodide, C 2 H 5 I, was free ethyl, C 2 H 5 . 

 Gerhardt, Hofmann, Laurent, Brodie, and Wurtz, how- 

 ever, sought to show that they should be represented by a 

 doubled formula : that the so-called ethyl, for instance, 

 had the composition C 4 H 10 = 2C 2 H 5 . This Frankland 

 strenuously opposed, mainly on the ground of the com- 

 plete homology of the hydrocarbons in question with 

 hydrogen, the formula of wnich was then almost univer- 

 sally written H. The arguments used were chiefly of a 

 physical character. Wurtz put an end to the controversy 



