MINERALOGY. 177 



and fomewhat ductile, both when crude* 

 and when melted. It cannot be decom- 

 poled without fome admixture of fuch fub- 

 itances as attract the acid of the fea-falt. 

 It is found in very thin worked or wrought 

 leaves or crufts, at Johan Georgenftadt, in 

 Saxony. 



SECT. CLXXVIII. 



Observations on the Silver Ores. 



Silver may, perhaps, be found niirieralifed in 

 the like manner with other metals than thefe here 

 enumerated, fuch as with cobalt and bifmuth-, but 

 having; no certain knowledge of fuch mineralifa- 

 tions, 1 omit them here. It would be worthy ex- 

 amining, if in thofe mine countries where gold 

 and fJver are found in quantity, other ores do not 

 contain a little of thofe metals, more efpecially 

 when the particles of filver and gold have not 

 been able to extricate themfeives from the other 

 minerals, and lie feparate from them in the fiffures, 

 veins, and ihakes or wranks, that is hollow places, 

 in the mines. 



Thofe filver ores which are named from earth 

 or ftones, wherein the filver is found \ as, for in- 

 ftance, in the Goofe-dung filver ore, and the Le- 

 ber ertz \ ought no more to be confidered in a na- 

 tural fyftern than other diftinctions which are ufed 

 at mineral works, and are only names given to 

 the ores, according to the fcveral changes they 

 •Undergo to make them fit for the melting procefs. 



In this our time a mineralifation of filver with 

 alcali has been mentioned : it is faid to have been 

 found at Annaberg inAuftria: But this difcovery, 

 which is made by a mine- matter, Mr. Von Jufti, 



N requires. 



