red that the cheap transmission of power by
the electric current will effect a more profound revolution in the
gold-mining industry than in almost any other. The main deterrent to
the investing of money in opening up a new gold mine consists in the
fact that a very large and certain expense is involved in the
conveyance of heavy machinery to the locality, while the results are
very largely in the nature of a lottery. When, however, the power is
supplied from a central station, and when economical types of crusher
are more fully introduced, this deterrent will, to a large extent,
disappear. The cables which radiate from the central electric
power-house in all directions can be very readily devoted to the
furnishing of power to new mines as soon as it is found that the older
ones have been proved unprofitable.

No one will think of carrying ore to the power when it is far more
economical and profitable to carry power to the ore. In this
connection the principle of the division of labour becomes very
important. In its bearing upon the mining industry generally, whether
in its application to the precious metals or to those which are termed
the baser, and even in the work of raising coal and other
non-metalliferous minerals, the fact that nearly all mines occur in
groups will greatly aid in determining the separation of the work of
supplying power, as a distinct industry from that of mining.

Ore-dressing is an art which was in a very rudimentary state at the
middle of the nineteenth century, when the great discoveries of gold,
silver and other metals began to influence the world's markets in so
striking a manner. The ancients used the jigger in the form of a
wicker basket filled with crushed ore and jerked by hand up and down
in water for the purpose of causing the lighter parts to rise to the
top, while the more valuable portions made their way to the bottom. In
this way the copper mines of Spain were worked in the days of the
Roman Empire, and probably the system had existed from time
immemorial.

Fifty or sixty years ago the miner had got so far as to hitch his
jigging basket or sieve on to some part of his machinery, generally
his pumping engine, and thus to avoid the wearing muscular effort
involved in moving it in the water by hand. It was not until the
obvious mistake of using a machine which permitted the finest, and
sometimes the richest, parts of the ore to escape had been for many
years ineffectually admitted