MINING. 247 
the particles of gold are so coarse in amalgam that they can 
easily be strained out by means of buckskin or tight cloths. 
ilowever a little gold will remain in the quicksilver—about 
the fiftieth part of an ounce of gold in every pound of quick- 
silver; and the only method of obtaining this gold is by re- 
torting. 
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 in- 
visible 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. Ifa 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 for- 
mer metals once touch, an amalgam is immediately formed, and 
if the proportions of the metals be about even, they in time 
make a hardmass. Some gold does not amalgamate readily; 
in various diggings of Siskiyou county, the gold has a red- 
dish 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 consid- 
ered 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 
