276 



PHYSIOGRAPHY. 



White Lead-Ore. 



figure. Massive : compostion often granular, or even im- 

 palpable, and strongly connected, more rarely columnar. 

 Faces of composition rough, or longitudinally or irregularly 

 streaked. 



1. Before the blow-pipe, it decrepitates, and changes its color into 

 yellow and red ; if properly managed, it yields a globule of metallic 

 lead. Reduced to powder, and thrown upon ignited charcoal, it emits a 

 phosphorescent light. It dissolves with effervescence in dilute nitric 



acid. 



2. Analysis. 



By KLAPROTH. 



Oxide of lead 

 Carbonic acid 

 Water 



82-00 

 16-00 

 2-00 



3. It occurs in veins and beds in various classes of rocks, accompani- 

 ed chiefly by Galena and other salts of lead. 



4. Fine crystallized varieties occur in the various mining districts of 

 Saxony, Hartz, Bohemia, Carinthia and France. Splendid crystals are 

 brought from the Daurian mountains in Siberia, on the frontiers of China. 

 Very beautiful varieiies are found at Wanlockhead and the Lead Hills in 

 Scotland, in the mines of Cumberland and of Cornwall. 



Very distinct and beautiful crystals were formerly obtained at the 

 Perkiomen Lead mine near Philadelphia. It also exists in Missouri, at 

 Valle's Diggings, Jefferson co. ; and in small quantity at the Southamp- 

 ton lead mine, (Mass.) 



