304 Elements of Mineralogy. 



weight of the precipitate, before and after 

 the application of the volatil alkali, gives the 

 quantity of the calx of filver, of which 129 

 gr. are equivalent to 100 of filver in its me- 

 tallic form. 



1 6. If the ore contains any foluble matrix, 

 which very feldom happens, it fhould firft be 

 feparated by boiling in diftilled vinegar. 2 

 Bergm. 424. 



17. In the dry way this ore may be eflfayed 

 by melting it with ^ of its weight of filings 

 of iron. 



SPECIES VI. 



Mineralized by Sulphur , 'with Silver and Re- 

 gulus of Antimony. 



Antlmonlal Lead Ore, Sproterz, Stripmalm. 



1 8. Its colour is the fame as that of Galena, 

 but its texture is different, being radiated, 

 filamentous, or ftriated ; when heated it yields 

 a white fmoke ; it affords from 40 to 50 per 

 cent, of lead, and from | an ounce to 2 ounces 

 of filver per quintal. 



It is effayed in the liquid way, by folution 

 in concentrated fpirit of nitre, which dephlo- 

 gifticates the regulus, and leaves it in the 



form 



