Silver*. 243 



The fiivef is precipitated by marine acid, or 

 common fait, and eftimated as in N- 4. The 

 PruJJian alkali will fhew if any other metal 

 is contained in the folution ; the gold, if 

 any, will remain undiflblved ; fixed alkalis 

 will precipitate any other earthy matters coia- 

 tained in the folution, 



9. In the dry way it may be reduced by 

 inciting it with the blow-pipe on charcoal ; 

 for the fulphur is diffipated^ and the filver re- 

 mains ; or by melting it with \ of its weight 

 of filings of iron, as the iron will take up the 

 fulphur and be fcorified. 



SPECIES III. 



Mineralized by a fmall proportion of Arfenic. 



10. This ore is of a yellowifh white co- 

 lour, and of a ftriated texture, refembling 

 bifmuth, bat much harder; it melts very 

 eafily^ and if kept in fufion, it lofes its 

 arfenic, and the filver remains almoft intirely 

 pure, as it contains but very little iron ; it 

 contains about 90 per cent, of filver, and is 

 found near >uadanal~Canal in Spain. Mon. 

 Mineral. 281. 



SPECIES IV. 

 Mineralized by a large proportion of Arfenic. 



1 1 . The proportion of arfenic in this ore 

 is fo great, that it would fcarce deferve to be 



R 2 called 



