carbon, in varying proportions, substances are produced, so
different, but each so valuable, that they might almost be regarded
in the light of distinct metals,--such, for example, as cast-iron,
and cast and bar steel; the various qualities of iron enabling it to
be used for purposes so opposite as a steel pen and a railroad, the
needle of a mariner's compass and an Armstrong gun, a surgeon's
lancet and a steam engine, the mainspring of a watch and an iron
ship, a pair of scissors and a Nasmyth hammer, a lady's earrings and
a tubular bridge.

The variety of purposes to which iron is thus capable of being
applied, renders it of more use to mankind than all the other metals
combined. Unlike iron, gold is found pure, and in an almost workable
state; and at an erly period in history, it seems to have been much
more plentiful than iron or steel. But gold was unsuited for the
purposes of tools, and would serve for neither a saw, a chisel, an
axe, nor a sword; whilst tempered steel could answer all these
purposes. Hence we find the early warlike nations making the backs of
their swords of gold or copper, and economizing their steel to form
the cutting edge. This is illustrated by many ancient Scandinavian
weapons in the museum at Copenhagen, which indicate the greatest
parsimony in the use of steel at a period when both gold and copper
appear to have been comparatively abundant.

The knowledge of smelting and working in iron, like most other arts,
came from the East. Iron was especially valued for purposes of war,
of which indeed it was regarded as the symbol, being called "Mars" by
the Romans.*
[footnote...
The Romans named the other metals after the gods. Thus Quicksilver