LEAD. 153 
Composition. PbO,C=Carbon dioxide 16°5, lead oxide 
83°5=100. B.B. decrepitates, fuses, and with care on char- 
coal affords a globule of lead. LHiffervesces in dilute nitric 
acid. 
Diff. Like anglesite, distinguished from most of the spe- 
cies 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. lLeadhills, Wan- 
lockhead, and Cornwall have afforded splendid crystalliza- 
tions ; also Linares, in Spain, and other lead mines on the 
continent of Europe. 
In the United States, handsome specimens are obtained 
at Austin’s Mines, Wythe County, Virginia, and at King’s 
Mine, in Davidson’s County, North Carolina; at the latter 
place it has been worked for lead, and it is associated with 
native silver and pyromorphite. Perkiomen and Phcenix- 
ville, Penn., afford good crystals. It occurs also at “ Valléc’s 
Digeings,” Jefferson County, Missouri, and other mines, in 
that State; at Brigham’s Mine, near the Blue Mounds, 
Wisconsin, partly in stalactites; at ‘‘ Deep Diggings,” in 
crystals; and at other places, both massive and in fine 
erystallizations. 
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, so 
extensively used as a paint. The materia! for this purpose 
is, however, artificially made. 
Phosgenite or Corneous Lead. A chloro-carbonate of lead, occurring 
in whitish adamantine crystals. H.—2-°75-4. G.=6-631. Composi- 
tion, PbO,C+PbCl. From Derbyshire and Germany. 
Hydrocerussite. Wydrous lead carbonate. From Sweden. 
Ganomalite is a white lead-manganese silicate, affording 34°89 per 
cent. of lead oxide. From Sweden. Ayalot. cite is a lead-barium-lime 
silicate. Both are from Longban, Sweden. 
General Remarks.—The lead of commerce is derived almost wholly 
from the sulphide of lead or galenite, the localities of which have 
already been mentioned. In some mining regions, the carbonate and 
sulphate are abundant. 
The lead mines of the Central United States afforded in 1826, 1,770 
tons ; in 1842, 17,310 tons; and of late years, 12,009 to 15,00) tons. 
