of this latter chemical will be based the main
improvements in the gold-mining industry during the twentieth century;
and, conversely, the applications of the old system of amalgamating
with mercury, in order to catch the golden particles, will be
gradually restricted. Fine concentrators, worked with cyanide
solution, perform three operations at once, namely, first, the
catching of the free gold grains; second, the production of a rich
concentrate of minerals having gold in association and intended for
smelting; and, third, the dissolving of the finest particles by the
continual action of the chemical.

In fact it is in the treatment of complex and very refractory ores
generally, whether of the precious or of the baser metals, that the
finer applications of the art of the ore-dresser will receive their
first great impetus. The vanner, as well as the jigger, will become an
instrument of precision; and in combination with rushing appliances
operated by cheap power in almost unlimited quantities it will
materially assist in multiplying the world's supply of metals. This
again will aid in promoting the further extension of machinery. Gold
will be produced in greater abundance for what is called the machinery
of commerce; and the base metals, particularly the new alloys of steel
and also copper and aluminium, will be more largely produced for
engineering and electrical purposes.

The importation--particularly to England and Scotland--of large
quantities of highly-concentrated iron ore will cause one of the first
notable developments in the mining and ore-treatment of the twentieth
century so far as the United Kingdom is concerned. The urgent
necessity for an extension in the manufacture of Bessemer steel, and
of the new and remarkable alloys in which very small quantities of
other metals are employed in order to impart altogether exceptional
qualities to iron, must accentuate the demand for those kinds of ore
which lend themselves most readily to the special requirements of the
works on hand. Hence the question of the transport of special kinds of
iron ore over longer distances will have to be faced (as it has been
already to a limited degree), and not only in reference to ores
containing a low percentage of phosphorus and therefore exceptionally
suitable for the Bessemerising process, but also in regard to ores
which are amenable to magnetic separation.

Magnetite, indeed, must bulk more largely in the future as a sourc