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PROCEEDINGS OF THE 



[Nov., 1857. 



The formation of the Chlorid of Purpureocobalt is effected by 

 simply oxydising the Chlorid of Cobalt with Ammonia by exposure 

 to the air. 



It is not necessary to use a pure Chlorid of Cobalt in forming 

 the Chlorid of Purpureocobalt; any commercial oxide answering, 

 even in the presence of arsenic, nickel, iron, and other impurities. 



A perfectly pure Chlorid of Cobalt is easily prepared from this 

 salt by heating it in a porcelain crucible until vapors of Ammonia 

 and Chlorid of Ammonium cease to be driven off. The pure 

 anhydrous Chlorid of Cobalt thus obtained is characterised by 

 beauty of color, forming pale blue talcose scales. 



To obtain the metal in a state of sponge, it is merely necessary 

 to reduce the chloride by means of Hydrogen.* In order to fuse 

 the metal, it is an indispensable precaution, to preserve its purity, 

 that it be effected by means of the lime crucibles as employed by 

 M. Sainte Claire Deville.*)" In connection with these crucibles, 

 he uses a lamp of peculiar construction, in which the vapor of 

 any liquid hydrocarbon, as oil of turpentine, is completely con- 

 sumed, by means of an artificial blast of air. I am unable, on the 

 present occasion, to reproduce the description, as it could not be 

 rendered with sufficient intelligence without the aid of a figure. 

 By means of this instrument the fusion of feldspar can be accom- 

 plished with facility. It has been found that the platinum metals 

 fused in these crucibles, present properties very different from those 

 heretofore attributed to them, the lime serving to deprive them of 

 osmium and silicon.]; 



As much carbon becomes mixed with Cobalt in the ordinary 

 method of fusion, one of its characters, that of ductility, becomes 

 entirely destroyed ; and a piece of the metal thus prepared, when 

 placed before the Oxyhydrogen Blowpipe, upon a brick, in which 

 a groove had been cut for the purpose of obtaining it in the form 

 of a bar, merely assumed an intumescent state, without exhibiting 

 any tendency to enter the incision. 



Since this, M. Debray has found that pure Molybdenum com- 

 pletely withstands the temperature, at which platinum, etc., 

 become liquid; and that its melting point, in a crucible of Carbon 

 before the Oxyhydrogen Blowpipe, is at a temperature at which 



*The preparation from the Oxalate will be treated of hereafter. 

 fAnnales de Chimie et de Physique, XLVI. p. 182, 1856. 



^"Dequelques methodes generates de preparation pour les corps simples." 

 Comptes Rendus de l'Acadamie des Sciences, XLIV. pp. 672-677. 



