OF ARKANSAS. 161 
remunerative. In England, the average quantity of silver contained in 
the lead which is worked for silver, is 7 or 8 ounces per ton, or about 6 or 
7 ounces perton of galena.* The galena, from the mines of the “Middle- 
town Silver and Lead Mining and Manufacturing Company,” in Connecti- 
cut, contains from 25 to 75 oz. of silver to the ton (of 21 cwts) of lead. 
The galena from the “ Washington mine,” North Carolina, contains only 
7.5 oz. of silver in the ton (average of 200 assays). *, 
ORES OF MANGANESE 
OF the five specimens of ores of manganese, subjected to analysis, two 
(Nos. 20 and 21) were collected on the spot; the other three, I received 
from a gentleman in Batesville, who collected them at the localities below 
mentioned. 
No. 20 Psilomelane, from the main manganese mine, two miles above 
West fork of Lafferty creek, Independence county: 
Massive; lustre submetallic; color between dark steel-gray and iron- 
black; hardness 5.5; fracture subcrystalline, hackly, somewhat resembling 
the fracture of cast iron; brittle; strikes fire with steel; powder reddish- 
brown. 
Before the blowpipe, infusible alone; on charcoal in reduction flame 
becomes reddish-brown; in a matrass, yields water; with fluxes, gives the 
manganese reactions. Dissolves in hydrochloric acid with evolution of 
chlorine, leaving a small residue of silica. 
Occurs in veins traversing the encrinital beds of the cavernous limestone. 
Composition, dried at 250 deg. F: 
Manganoso-manganic oxide (Mn90‘)...--++++++- 91.367 
Silica «+ sce ee eee eter ween ee ee tant n eee enene 9.845 
ots Sei ees eee enee 0.512 
Lime: ++seceeooee eee cece en reer en eeeee trace 
100.655 
The air-dried mineral lost 0.53 per cent. of moisture at 250 deg. F. 
* See J. D. Whitney’s “Metallic Weulth of the United States.” Philadelphia, 1854. 
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