232 METALS. 



compound crystals, either six-sided prisms like aragonite, or 

 wheel-shaped groups of 4 or 6 rays (fig. 3.) Also massive 

 rarely fibrous. 



Color white, grayish, light or dark. Luster adamantine. 

 Brittle. H=3— 3*5. Gr = 6*46— 6*48. 



Composition : oxyd of lead 83*46, carbonic acid 16*54 

 Decrepitates before the blowpipe, fuses, and with care af- 

 fords a globule of lead. Effervesces in dilute nitric acid. 



Dif. Like anglesite, distinguished from most of the 

 species it resembles by its specific gravity and yielding lead 

 when heated. From anglesite it differs in giving lead alone 

 before the blowpipe, as well as by its solution and efferves- 

 cence with nitric acid, and its less glassy lustre. 



Obs. Associated usually with galena. Leadhills, Wan- 

 lockhead, and Cornwall, have afforded splendid crystalli- 

 zations ; also other lead mines on the continent of Europe. 



In the United States, very handsome specimens are ob- 

 tained at Austin's mines, Wythe county, Virginia, and at 

 King's mine in Davidson's county, North Carolina. At the 

 latter place it constitutes a wide vein, and has been worked 

 for lead. It is associated with native silver and phosphate 

 of lead. Perkiomen and Phenixville, Perm., afford good 

 crystals. It occurs also at " Vallee's Diggings," Jefferson 

 county, Missouri ; at Brigham's mine near the Blue Mounds; 

 Wisconsin ; at " Deep Diggings" in crystals ; and at other 

 places in the West, both massive and in fine crystallizations. 

 Rossie, N. Y., and Southampton, Mass., have afforded this 

 ore. 



Uses. When abundant, this ore is wrought for lead. Large 

 quantities occur about the mines of the Mississippi valley. 

 . It was formerly buried up in the rubbish as useless, but it 

 has since been collected and smelted. It is an exceedingly 

 rich ore, affording in the pure state 75 per cent, of lead. 



Carbonate of lead is the " white lead" of commerce, sc 

 extensively used as a paint. The material for this purpose 

 is, however, artificially made. In most manufacturing es- 

 tablishments, sheets of lead are suspended over a liquid made 

 of vinegar and wine lees, and a gentle heat is applied either 



What are the color and luster of white lead ore? its composition and 

 blowpipe reaction I How is it distinguished from anglesite 1 How 

 rrom minerals not lead ores ? What use is made of white lead 1 How 

 is white lead manufactured 1 



