ANALYSIS OF IRON ORES, &C. 3/ 



time the quantities he has assigned to its different compo- Quantities 

 nent parts he gives only as approximations. mat^io^i's^'^°^^* 



Ten grammes [154'5 grs.] of the ore of Drambon, treat- q re of Drara- 

 ed with caustic potash, assumed a very intense green co- boa, 

 lour, that communicated itself to the water in which it was 

 lixiviated. The ore being subjected to the same operation 

 a second time, it produced a similar effect, but less strik- 

 ing. 



The liquors were boiled, and 3 decig. [4*6 grs.] of man- Manganese, 

 „ ,, J ^ • • i-^^i 1 ji ^ „sU ex, and iron. 



ganese tell down, coutaimug a little silex, and an atom ot 



iron. 



The solution retained a slight yellow colour, as in that 

 from the scoria*; and Mr. Vauquelin, supposing this coloxir 

 to be produced by the same substance, saturated it with ni- 

 tric acid. With this liquor he mixed a solution of nitrate 

 of mercury made without heat ; when it became colourless, 

 and a white precipitate fell down, that did not give any tinge 

 to glass of borax. 



As the liquor contained an excess of acid, it was sus- Chrome, 

 pected, that, if any chromate of mercury had been formed, 

 it was held in solution. Accordingly a few drops of a so- 

 lution of pure potash were added, and a brown red preci- 

 pitate was obtained, which, being fused with borax, gave 

 it a fine emerald green. This indicated, that it was chro- ana perhaps 

 mate of mercury, perhaps with a little phosphate of the ^^.^^ °"^ 

 same metal. 



The liquor being still acid, and retaining some mercury 

 in solution, Mr. Vauquelin imagined it still contained 

 chrome. He therefore added a few drops of nitrate of sil- 

 ver, in hopes of obtaining a crimson red precipitate ; but 

 what fell down was of an orange yellow, and did not give a 

 green colour to borax. It was phosphate of silver. Potash Phosphoric . 

 added to the remaining liquor produced a very bulky, floe- **^ 

 culent, lemon-coloured precipitate. This acquired a green 

 hue as it dried, and was chromate of mercury, containing Chrome, a'u- 

 silver, with a small quantity of alumine and silex. "^"^*'' ^ *' *** 



The mercury was separated from the silver in a gentle 

 heat by means of muriatic acid, diluted with two parts of 

 water, that it might not dissolve the muriate of silver. At 

 once the precipitate became white, and the acid green. The Chr© n«. 



olution 



