en the principal work of amalgamation is done
(experience soon teaching the amount of grinding necessary), from the
Chilian mill the paste (so to say) is passed to a Wheeler or any
other good pan of a similar type, when the gold-saving operation is
completed."

This being an experiment in the same direction as my own, I tried it on
a small scale. I calcined some very troublesome ore till it was fairly
"sweet," triturated it, and having reduced it with water to about the
consistency of invalid's gruel, put it into a little berdan pan made
from a "camp oven," which I had used for treating small quantities of
concentrates, and from time to time drove a spray of mercury, wherein a
small amount of zinc had been dissolved, into the pasty mass by means
of a steam jet, added about half an ounce of sulphuric acid and kept the
pan revolving for several hours. The result was an unusually successful
amalgamation and consequent extraction--over ninety per cent.

Steam--or to use the scientific term, hydro-thermal action--has played
such an important part in the deposition of metals that I cannot but
think that under educated intelligence it will prove a powerful agent
in their extraction. About fourteen years ago I obtained some rather
remarkable results from simply boiling auriferous ferro-sulphides in
water. There is in this alone an interesting, useful, and profitable
field for investigation and experiment.

The most scientific and perfect mode of gold extraction (when the
conditions are favourable) is lixiviation by means of chlorine,
potassium cyanide, or other aurous solvent, for by this means as much as
98 per cent of the gold contained in suitable ores can be converted into
its mineral salt, and being dissolved in water, re-deposited in metallic
form for smelting; but lode stuff containing much lime would not be
suitable for chlorination, or the presence of a considerable proportion
of such a metal as copper, particularly in metallic form, would be fatal
to success, while cyanide of potassium will also attack metals other
than gold, and hence discount the effect of this solvent.

The earlier practical applications of chlorine to gold extraction were
known as Mears' and Plattner's processes, and consisted in placing the
material to be operated on in vats with water, and introducing chlorine
gas at the bottom, the mixture being allowed to stand for a number
of hours, the minimum about twelve, the maximum forty-eight. The
c