AI^ALYSIS OF A MINERAL, &C. J^ 



Upon examination, this appeared to be principally fulphuret 

 of lead, which, like a cruft, enveloped a minute globule of 

 metallic copper, fo malleable as to bear to be flattened by a 

 hammer. 



in. 



Some of the ore, finely powdered, was put into a matrafs, Digeftion with 



and nitric acid diluted with an equal poison of water was acid^^«tc!Tmfica- 



poured on it. Upon being digefted in a low heat, a contiderable ted fulphur, lead, 



part, was difTolved, with much effervefcence. Some fulphur, *^°PP"» *"'*. f " 

 , . , - ' timony, with S| 



which floated, was feparated ; and the clerfr liquor, which was little iron. 



bluifti green, was decanted from the reliduum at the bottom of 



the veflel. 



A great part of the excefs of acid being expelled from the 

 folution, it was largely diluted with diflilled water, and fome 

 diflblved muriate of foda was added ; but this did not produce 

 any alteration in the tranfparency of the liquor. A folution of 

 fulphate of foda was then poured in, and formed a very copious 

 precipitate of fulphate of lead. 



When this had been feparated, the liquor was faturated with 

 ammonia ; by which it was changed to a deep blue colour. A 

 few floccuii of iron were feparated ; and the remainder was 

 found to contain nothing but copper. 



The fulphur which had floated, was added to the refiduum 

 which had fubfided to the bottom of the matrafs; and the whole 

 was digefted with muriatic acid. This folution was of a flraw 

 colour; and, when feparated from the fulphur, and poured into 

 a large quantity of water, afforded a plentiful while pre- 

 cipitate. 



This precipitate was completely refolved into white fumes, 

 by the blowpipe; and the muriatic folution of it, when added to 

 water impregnated with hydro-fulphuret of ammonia, formed 

 the orange coloured precipitate, commonly known by the ap- 

 pellation of golden fulphur of antimony. 



IV. 



Muriatic acid did not immediately a6t upon the pulverized The fame refult* 

 ore ; but a folution was fpeedily effected by the addition of a ^X treatment 

 few drops of nitric acid : pure fulphur was feparated ; and the acid and a little 

 liquor, being decanted into water, yielded a copious precipitate """«• 

 of oxide of antimony. 



4 The 



