Lead. 301 



SPECIES III. 

 Mineralized by the Vitriolic acid. 



I i. According tvMr.Monneti this fometimes 

 occurs in the form of a white ponderous calx, 

 foluble in 1 6 or 1 8 times its weight of water. 

 It does not effervefe, nor is it foluble in other 

 acids ; it may be reduced by laying it on a 

 burning coal. It originates from the fpon- 

 taneous decompofition of fulphurated lead 

 ores. Mon. Mineral. 371. According to Dr; 

 Withering^ it is found in great quantity in 

 the ifland of Anglefy, but united to iron, and 

 not reducible by the blow pipe or charcoal, 

 he promifes an exact analyfis of it, this is of 

 a yellow colour, and mixed with clay. 



SPECIES IV. 

 Mineralized by the Phofphoric acid. 



12. This was lately difcovered by Mr. 

 Gahn ; it is of a greenifh colour, by reafon of 

 a mixture of iron ; it does not effervefce with 

 acids. 



To eflay it, a folution of it in nitrous acid 

 muft be had, with the affiftance of heat. 

 From this folution, the lead is to be precipi- 

 tated by the acid of vitriol. 137 gr. of this 

 precipitate, wafhed and dried* are equivalent 



to 



