smelted by mixing with it fifty per cent. of lead in metal or ore,
and ten per cent. of iron, and exposing the whole to a heat sufficient
to melt the silver which runs off. The metal thus obtained is not pure
but contains much lead, which is driven off by heat while the silver is
kept in a molten condition for a period of four or six hours. The cost
of smelting in California at present, is about one hundred and
twenty-five dollars per ton. In most of the other methods of reducing
silver ore, the ore is roasted to drive off the sulphur. In the barrel
amalgamation, which has been used at Washoe, and will probably be used
at Esmeralda also, half a ton of ore, after being pulverized and
roasted, three hundred pounds of water, and one hundred pounds of
wrought iron, in little fragments, are put into a barrel, which
revolves on a perpendicular axis. At the end of two hours the mass has
taken the consistence of thick cream, when five hundred pounds of
quicksilver are put in, and after the barrel has revolved four hours
more, the amalgamation is complete. More water is now poured in; the
barrel revolves very slowly to let the amalgam all settle to the
bottom, the mud runs off through a cock four inches above the bottom,
and the mercury and amalgam are then drawn off through a little hole in
the bottom of the barrel.

_Quicksilver Mining._--The ore from which quicksilver is obtained is a
sulphuret. The sulphur is driven off by heat, and the metal, which
rises in fumes from the ore, is collected by condensation. The miners
are Cornishmen and Mexicans. The ore is in large masses underground,
not in a connected vein of regular thickness; and after one mass is
exhausted, much labor is often vainly spent in search of another. There
are, however, usually little seams of ore running from one large
deposit to another, and it is the business of the mining captains to
observe these veins closely, and trace them up when a "fault" occurs.
There are no scientific rules for finding the ore; and the business of
searching for the large deposits is never intrusted to educated mining
engineers, but always to mining captains, who have themselves been
laborers, and have learned by experience where to seek. The New Almaden
mine produces two hundred and twenty thousand pounds of metal in a
month. The _hacienda_, or reducing establishment of the mining company,
has fourteen brick furnaces, each fifty feet long, twelve feet high,
and twelve feet wide.