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NATURE 



\ytily 7, 1 88] 



to devote himself almost exclusively to the inorganic 

 branch, and announced in 1849 his first grand discovery, 

 that of nitric oxide. By demonstrating the existence of 

 this interesting and important compound, as resulting 

 from the action of chlorine on silver nitrate, 2AgN03 + 

 CL = 2AgCl + + N2O5, Deville did much to stimu- 

 late the theoretical speculation of the day, especi- 

 ally among the opponents of the school of Gerhardt, 

 whose theories did not recognise the possibility of the 

 existence of monobasic acid anhydrides. After a few 

 years devoted to varied studies of metallic carbonates 

 and new analytical processes, he commenced in 1855 the 

 famous research on metallic aluminium, which proved to 

 be one of the crowning features of his lifework. Furnished 

 with ample means by the munificence of Napoleon 111., 

 he was enabled to carry out experiments on a large scale, 

 and so rapid was his success that even in 1855 he i^'is- 

 played at the Exhibition of Paris massive bars of this 

 handsome metal, which previously had scarcely been 

 seen in a pure state. The study of this metal and its 

 metallurgical production, as well as of the various com- 

 pounds of aluminium, carried out during a series of years, 

 forms one of the most remarkable and complete contribu- 

 tions made to inorganic chemistry within a recent period. 

 Deville's perfected process for the preparation of aki- 

 minium, as carried out in the two French and the single 

 Englishestablishment in which alone this metal is obtained, 

 consists essentially in heating the double salt of aluminium 

 and sodium, AlCls.N-ACl, with metallic sodium, fluor- 

 spar or cryolite being added as a flux. The metal thus 

 obtained in the form of a solid regulusis used for a large 

 variety of objects where lightness, strength, and freedom 

 from oxidation are demanded, and forms the essential 

 part of numerous valuable alloys. It has failed partly to 

 meet the extended use to which Deville looked forward, 

 on account of its comparatively high price and the diffi- 

 culty of welding the metal. Among other industrial 

 branches which we owe to Deville's efforts to 

 create the manufacture of aluminium, such as the 

 production of bauxit and cryolite, mention shoifld 

 especially be made of the manufacture of metallic 

 sodium, the price of which sank in ten years from 

 2,000 francs to 15 francs per kilogramme. Deville's 

 researches in this direction and his various methods of 

 manufacture are to be found in iwtenso in his classical 

 work, Dc r aluminium, ses propricti's, S-^c, 1S59. In union 

 with Caron he applied in 1S63 the method found success- 

 ful in the case of aluminium to the production of magnesium, 

 and thereby created a second branch of industry. The 

 manufacture of this metal, although confined to an annual 

 production of about ten tons, is fully as interesting and 

 ingenious as that which places aluminium within the reach 

 of the industrial and scientific world. In this connection 

 mention should be made of his exhaustive researches, 

 chiefly in company with Ddbray, on the metals of the 

 platinum group (1859 — 1862), in the course of which he 

 succeeded for the first time in fusing large quantities of 

 platinum by means of the oxyhydrogen blowpipe. The 

 phenomena accompanying the high temperatures so all- 

 important in the metallurgical operations just alluded to, 

 gradually assumed a leading place amongst the subjects 

 of Deville's researches. After successfully devising lamps 

 and furnaces by means of which a high degree of heat was 

 attainable, and methods by which the temperature could 

 be measured, he proceeded to study a variety of reactions 

 taking place at temperatures scarcely reached before his 

 time. First among the results obtained in this direction 

 reference should be made to the variety of crystallised 

 minerals prepared artificially, such as willemite,greenockite, 

 zircon, periclase, staurolite, &c. This branch of research 

 has been so ably followed up by scholars of Deville, that 

 but few natural minerals exist nowadays of which artificial 

 counterparts have not been prepared. C'f much greater 

 importance were the numerous determinations of the 



vapour densities of bodies which are ordinarily solid, 

 such as the chlorides of aluminium, of iron, and of 

 various rare metals, by means of which the molecular 

 weights of numerous coinpounds have been satisfactorily 

 obtained. By far the most important of Deville's thermal 

 investigations, those which have rendered the grandest 

 services to theoretical chemistry, are connected with his 

 noted discovery of the principle of dissociation in 1857. 

 This principle, which explains a variety of hitherto ano- 

 malous occurrences among thermal phenomena, may 

 briefly be considered as the property of many com- 

 pound bodies to undergo partial decomposition under 

 the influence of heat in confined spaces, until the 

 liberated gas or vapour has attained a certain tension 

 greater or less according to the temperature. So long 

 as this temperature remains constant, no further decom- 

 position takes place, neither does any portion of the 

 separated elements recombine. If the temperature be 

 raised decomposition recommences, and continues until 

 a higher tension of the liberated gas or vapour, definite 

 for that particular temperature, is attained. If the tem- 

 perature falls, recomposition ensues, until the tension ot 

 the residual gas is reduced to that which corresponds 

 with the lower temperature. The enunciation of this 

 simple, but far-reaching principle has thrown light 

 upon a number of phenomena, such as the formation of 

 minerals, the apparent volatilisation of solids, &c., and 

 has been the fruitful source of countless novel dis- 

 coveries. 



The number of different subjects touched upon by 

 Deville during his long career of investigation, has been 

 so great that we are forced to simply allude in conclusion to 

 several notable researches, such as that on boron in com- 

 pany with W'ohler (1857), preparation of silicium, and its 

 compounds with copper (1863), a new calorimeter, and 

 the changes attendant upon the mixture of liquids (1870), 

 the examination of a large variety of minerals and 

 natural products, &c. 



In reviewing the lifework of Sainte-Claire Deville, we 

 are struck constantly by the predominance of one quality 

 — that of simplicity ; a quality so eminently character- 

 istic of the man in his social relations, as well as in his 

 scientific labours, that perhaps no phrase could describe 

 him better than that of the French Bunsen. Like his 

 great fellow-worker across the Rhine, he has been able 

 to find abundant material for the exercise of his 

 genius in attacking the still unsolved problems of in- 

 organic chemistry ; like him also he has held himself 

 aloof in a great measure from the poletnics prevalent in 

 the modern school of chemists ; the same charming 

 simplicity characterises his apparatus, his methods, the 

 few fundamental principles he has enunciated. As a 

 professor Deville was deeply beloved by his students, to 

 whom he was in turn greatly devoted ; responding readily 

 to all demands on his time and thought, and making use 

 of his vast influence to further the interests of those who 

 evinced special merit. His proverbial tenderness towards 

 trembling candidates in the public examinations rendered 

 him eminently popular in student circles. 



"Voyons, Monsieur, de quoi est composc^e I'eau ? . . . 

 d'O ?" 



" Xygene," repondait I'eleve. 



" Et encore ? . . . d'hy . . . ? " 



" Drog&ne," ajoutait le candidal. 



" C'est cela, IMonsieur, merci !" 



Sainte-Claire Deville was elected a member of the 

 French Academy in 1861. A year before he had been 

 elected a honorary member of the Chemical Society of 

 London. He was the recipient of numerous other marks 

 of recognition from foreign societies and governments. A 

 few years since he received the commission of preparing 

 the normal international metre measure, a task which 

 brought upon him much labour. While holding aloof 

 from politics, Deville was highly regarded in the business 



