ng an amalgam with the quicksilver, remain at the bottom. We
have no texture so fine that it will strain salt out of water; but the
particles of gold are so coarse in amalgam that they can easily be
strained out by means of buckskin or tight cloths. However, a little
gold will remain in the quicksilver--about the fiftieth part of an
ounce of gold in every pound of quicksilver; and the only method of
obtaining this gold is by retorting.

Quicksilver is used in gold mining for catching the small particles of
metal; the large ones are caught by their weight. But many of the
particles are so small that they are almost invisible to the naked eye,
and when in moving water they float. Miners frequently show visitors
the fineness of their gold by putting some of the dust in a vial with
water, and upon shaking, the particles of metal can be seen floating
about in the clear water. Riffles, and all the devices to get the
benefit of specific gravity, are of little use to arrest this
"float-gold," so amalgamation is employed. If a bit of quicksilver is
put in the way of the fine gold, the two metals unite at once and make
a larger bulk, which can be caught.

There is no such attraction between gold and quicksilver as there is
between the magnet and iron; but when the two former metals once touch,
an amalgam is immediately formed, and if the proportions of the metals
be about even, they in time make a hard mass. Some gold does not
amalgamate readily; in various diggings of Siskiyou county, the gold
has a reddish coating, which prevents amalgamation. Grease or resin in
the water used for washing, is also unfavorable. So is cold. Heat is
favorable, and therefore less gold is lost in summer than in winter.
Quicksilver that has been once used is considered better than that
fresh from the flask.

No tinned iron or copper vessel should be used for holding or panning
out amalgam, or dirt containing amalgam; since quicksilver forms an
amalgam with tin and copper, and will stick to the sides of a tinned or
copper pan.

In most sluices, the quicksilver is put in above the riffle-bars at
various places along in the boxes, with a confidence that the great
specific gravity of the metal will prevent it from being lost. The
greater the quantity and proportion of fine gold, the greater the
importance of the quicksilver.

The best method of catching very fine gold by amalgamation is to cover
a large copper plate with mercury, and let the dirt a