Iron. 305 



form of a calx. 138 gn of this calx are equi- 

 valent to 100 of the regulus. Or ftill better, 

 by folution in fpirit of fait which diflblves 

 both the lead and regulus, and leaves the * 

 fulphur and ftony matter which are feparable, 

 as fhewn in N? 14. If water be poured on 

 the folution, the calx of antimony will be 

 feparated. 



SPECIES VII. 



Mineralized by Sulphur, with Silver and a 

 large Proportion of Iron. 



Pyritous Lead Ore, 



20* This is of a brown or yellowish co- 

 lour, of an oblong or ftaladlitieal form, 

 friable, and of a lamellar, ftriated or loofe 

 texture; it affords at moil 1 8 or 20 per 

 cent, of lead, which flows by barely heat- 

 ing it, as the iron detains the fulphur; it is 

 no more than a mixture of galena with the 

 brown pyrites, Chap. 5. N? 31. 



SPECIES VIII. 



Mineralized by Sulphur and Arfemc y 'with 

 Silver. 



Red Lead Spar. 



21. Lately difcovered in Siberia*, exter- 

 nally it is of a pale and internally of a deep 



X red, 



