24 ANALYSTS OF IJlON ORES, &C. 



flocks, whicli, when collertecl, washed, and dried, weighed 

 2 decig. [3 grs.] amounting to 4 per cent. 

 Chroiresus- The alkaline liquor, freed from the manganese and fiU 

 pected. tered, stiil retained an orange yellow colour, which led Mr. 



Vauquelin to buspect the presence of chrome. 

 ?n?x and alu- Yov verifying this suspicion, it was necessaiy, in order to 

 'dted ^^ facilitate the operations necessary for detecting the chrome^ 



to separate the alumine and silex, that were in the alkaline 

 lixivium; and to avoid the presence of muriatic acid, which 

 would have ihv arted the end he proposed, Mr. Vauquelin 

 employed very pure nitrate of ammonia, instead of the mu- 

 riate. Thus he obtained 2 cent. [0*3 gr.] of a mixtvire of si^ 

 lex and alumine. 

 Carbonic acid He then saturated the liquor with very pure nitric acid, 



expelled by ni- j^-^ ]jjj.lg \^ excess, and boiled it for a qtiarter of an 

 trie & boiling. _ ' ... 



hour, in order to dissipate the carbonic acid entirely. 



Nitrate of mer- To a portion of the liquor thus prepared he added a few 

 tated ulfos'uho- ^•"op* of the solution of nitrate of mercury at a minimum ; 

 ric acid. but instead of these giving it a red colour, as is usual with 



chrome, they threw down a white precipitate, which at first 

 he took for muriate of mercury, but it afterward iippeared 

 to be phosphate of mercury. 

 Limewatcr Instructed by this trial, he added to the remainder of the 



threw down liquor limewater, which, when the acid was saturated, pro- 

 '"°'^^' duced a flocculent precipitate. This had a slight tint of 



yellow, which changed to a green on drying, a circumstance 

 that indicated some foreign matter in the phosphate of 

 lime. 

 Chrome. Desirous of discovering the cause of this colour, he heat- 



ed the precipitate red hot in a silver crucible ; in conse- 

 quence of which the green tint, instead of disappearing, 

 became more intense. He then fused a little with borax 

 by the blowpipe, and the fine emerald green colour the salt 

 assximed confirmed his first suspicion of the existence of 

 chrome in the scorice from the refining furnace. 

 Oxide of The remainder of the precipitate, being treated with ni- 



chrome with a (nc acid, was not entirely dissolved ; a portion being left of 

 a very deep green colour, which was nothing but oxide of 

 chrome mixed with a little silex, the particles of which being 



brought 



