ANALYSIS OF A NEW SfPECIES of LEAD-ORE. 



grains. The 3.7 grains driven off, I considef 

 as sulphur. 



The white powder was now exposed to a red 

 heat in a platinum crucible, but it did not lose an^ 

 weight. Before the blow-pipe, upon charcoal, it 

 was speedily reduced, and a button of metallic lead 

 obtained. It was easy to recognize by these pro- 

 perties, that the powder was sulphate of lead. 



The acid liquor being evaporated nearly to dry- 

 ness, an additional portion of white powder sepa- 

 rated, which, being washed and dried, weighed 

 16.6 grains. It was likewise sulphate of lead. 



Thus, 100 grains of the ore yielded 71.4 grains 

 of sulphate of lead. Now, this salt is a compound 

 of Yellow oxide of lead, 52.61 



Sulphuric acid, - 18.79 



71.40 



From the table given in the Annals of Philoso- 

 phy, vol. ii. p. 42., it is easy to see that 52.61 

 grains of oxide of lead, contain 48.849 grains of 

 lead. From the same table, we may ascertain,- 

 that 18.7^ grains of sulphuric acid contain 7.51& 

 grains of sulphur. 



The liquid from which the last portions of sul- 

 phate of lead had been separated, being set aside 

 for a few days, let fall small tetrahedral crystals of 

 a white colour, which I recognized by their form 

 to be nitrate of lead. They weighed 2.13 grains, 

 and contained 1,21 grains of lead. Thus, the 



