M. SAINTE-CLAIRE DEVILLE. 545 



scribed its preparation by the action of chlorine on silver nitrate, and 

 its properties. The possibility of the existence of monobasic acid an- 

 hydrides had previously been disputed. In 1852 he published in the 

 "Annales de Chimie et de Physique" an important paper upon the 

 metallic carbonates and their combinations, and in 1853 he discovered 

 a new method of mineral analysis. In 1855 he began the famous re- 

 search on metallic aluminium, which proved, says his biographer in 

 " Nature," to be one of the crowning features of his life-work. He 

 was furnished the means by which he was enabled to carry his experi- 

 ments to success by Napoleon III, who was looking forward to the 

 application of the qualities of a metal of so light a specific gravity to 

 the making of armor and helmets for the French cuirassiers. The 

 anticipation proved to be a mere dream, and impracticable ; but the 

 ambition in which it was bred was caused for once to minister to the 

 lasting benefit of mankind. With the means thus furnished, M. De- 

 ville was able to carry on his experiments on a large scale, and so rap- 

 idly that even in the same year in which he began he displayed at the 

 exhibition in Paris massive bars of the metal, that had hardly been 

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

 lurgical production, as well as of the various compounds of aluminium, 

 carried out during a series of years, forms, says " T. H. N." in " Nat- 

 ure," one of the most remarkable and complete contributions made to 

 inorganic chemistry within a recent period. The metal is now pre- 

 pared in one English and two French establishments according to 

 Deville's perfected process, which consists essentially in heating the 

 double salt (chloride) of aluminium and sodium with metallic sodium, 

 fluor-spar or cryolite being added as a flux, and is used for a variety 

 of objects where lightness, strength, and freedom from oxidation are 

 demanded, and in many valuable alloys, of which it forms the essential 

 part. It has not come into as extensive use as Deville hoped it might, 

 for it is still too high in price and is hard to weld. The operations 

 with aluminium have resulted in building up other industries, such as 

 the production of bauxite and cryolite, and the manufacture of metal- 

 lic sodium, the price of which sank in ten years from two thousand 

 francs to fifteen francs per kilogramme. In 1863 M. Deville, in con- 

 nection with Caron, applied his aluminium method to the manufacture 

 of magnesium, and made it possible to produce that metal in commer- 

 cial quantities. With Debray he carried on exhaustive researches 

 from 1859 to 1862 on the metals of the platinum group, in which be 

 applied the oxyhydrogen blow-pipe on a large scale to the fusion of 

 platinum, now for the first time accomplished. This led him to oper- 

 ations at higher temperatures than had ever before been attained, ex- 

 cept perhaps casually, involving the artificial production of crystalline 

 minerals, which has since been carried out by other chemists to a larger 

 extent, and numerous determinations of the vapor densities of bodies 

 that are ordinarily solid, like the chlorides of aluminium, iron, and va- 

 vol. xx. 35 



