tiful gold ornaments have been found that were
made by the prehistoric peoples who once occupied ancient Etruria, in
Italy. Columbus found gold ornaments in the possession of the aboriginal
Americans. The Incas of Peru and the Aztecs of Mexico possessed large
quantities of gold.

[Illustration: LEACHING (CYANIDE) TANKS DISSOLVING THE GOLD FROM THE
ROASTED ORE]

[Illustration: STOPING OUT A TUNNEL]

[Illustration: INTERIOR OF MILL]

[Illustration: GOLD MINING]

Gold is one of the most widely diffused of metals. Traces of it are
found in practically all igneous and most sedimentary rocks. It occurs
in sea-water, and quite frequently in beach-sands. Traces of it are also
usually to be found in alluvial deposits and in the soils of most
mountain-folds. In spite of its wide diffusion, however, all the gold
that has been mined could be stored readily in the vaults of any large
New York bank.

In all probability most of the gold now in use has been deposited by
solution in quartz veins, the latter usually filling seams and crevices
in granitic or volcanic rocks. Quartz veins seldom yield very great
returns, but they furnish a steady supply of the metal. The rock must be
mined, hoisted to the surface, and crushed. The gold is then dissolved
by quicksilver (forming an amalgam from which the quicksilver is removed
by heat), by potassium cyanide solution, or by chlorine solution.

In many instances the quartz veins have been broken and weathered by
natural forces. In such cases the gold is usually carried off by swiftly
running water and deposited in the channel lower down. In this way
"placer" deposits of gold occur. Placer deposits are sometimes very
rich, but they are quickly exhausted. The first gold discovered in
California was placer gold.

Nearly all the gold mined in the United States has come from the western
highlands. In 1900, Colorado, California, South Dakota (Black Hills),
Montana, and Alaska yielded about seven-eighths of the entire product.
The placer mines of Alaska are confined mainly to the beach-sands and
the tributaries of Yukon River. Since 1849 the average annual yield of
gold in the United States is about forty-three million dollars.

The Guinea coast of Africa, Australia, California, the Transvaal of
South Africa, and Venezuela have each stood at the front in the
production of gold. The aggregate annual production of the world has
increased from one hundred and sixty million dollars in 1853 to m