Analysis of Iron Ores, &c. 17 



The liquors were boiled, and three decig. (4*6 grains) of 

 manganese fell down, containing a little silex, and a minute, 

 portion of iron. 



The solution retained a slight yellow colour, as in that 

 from the scoriae. M. Vauqueiin, supposing this colour to 

 be produced by the same substance, saturated it with nitric 

 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, which did not give any tinge 

 to glass of borax. 



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

 ed, that, if any chromate of mercury had been formed, it 

 was held in solution. Accordingly a few drops of a solu- 

 tion of pure potash were added, and a brown red precipitate 

 was obtained, which, being fused with borax, gave in a fine 

 emerald green. This indicated, that it was chromate of mer- 

 cury, perhaps with a little phosphate of the same metal. 



The liquor being still acid, and retaining some mercury 

 in solution, M. Vauqueiin 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 

 added to the remaining liquor produced a very bulky, floc- 

 culent, lemon-coloured precipitate. This acquired a green 

 hue as it dried, and was chromate of mercury, containing 

 silver, with a small quantity of alumine and si lex, 



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 

 solution being evaporated to dryness left a blackish matter, 

 which gave a very fine green colour to borax. 



Afterward, by employing sulphuric acid, and precipitating 

 by limewater, M. Vauqueiin obtained 1 *5 per cent, of 

 magnesia. Though this earth was found in the pig iron 

 from each of the five bog ores, he does not venture to assert 

 that it exists in all : but he observes, he has much more rea- 

 t Vol. 33. No. J 29-. Jan. 1809. B so* 



