316 Chemical Composition of the Brown Lead Ore. 
Oxide of lead, - - - - - 81.460 
Muriatic acid, - = ~ - 1.956 
Lime, YO EMI AT orbs 0- 1, 0.320 
Phosphoric and fluoric acids, and loss, - 16.264 
100.000 
The constitution of this Brown Lead Ore, estimated by the prece- 
ding formula, and based upon the ascertained proportions oh chlorine 
and oxide of lead, is as follows : 
Chloride of lead, - - - - 9.918 
Fluoride of calcium, - - - 0.137 
eae phorphate of lead, - - - 89.174 
ligiessa tenant une 0.771 
: 100.000 
5. Crystallized Brown Lead Ore from England.—This Brown 
Lead Ore forms upon Galena, delicate needle-shaped crystals of a liver- 
brown color, which are perfectly transparent, and of an adamantine 
luster. Iam not exactly informed of the precise locality of this va- 
riety : I purchased my specimens, furnished with the above ticket in 
German, last year at Lyons of a mineral-dealer, named Lafont. Be- 
fore the blowpipe, it exhibits the same reactions as the varieties be- 
fore enumerated. When treated with soda, no smell of arsenic was 
afforded ; neither did its solution tested in several ways afford any 
signs of the presence of this metal. Examined with sulphuric acid, 
I easily obtained though only in a feeble manner, signs of the pres- 
ence of fluoric acid: in like manner also a very small proportion of 
lime was rendered obvious, by adding, after the separation of the 
lead, to the concentrated solution, sulphuric acid mingled with alco- 
hol. The analysis of this ore could only be performed upon 0.9 
grammes, which gave for the one hundred parts, 
Oxide of lead, - - - - - 82.083 
Muriatic acid, - - - - 1.990 
Lime, - - - - - 0.320 
Phosphoric and fluoric acids with loss, 15.607 
100.000 
These results, estimated agreeably to the formula adopted above, 
and calculated upon the basis of the quantities of oxide of lead and 
muriatic acid ascertained in the analysis, give, . 
