ON METALS. 273

great propensity to dance and jump about, for Mercury,
you know, was very nimble.

G. Yes; he had wings to his heels.

2’. Copper is Venus.

G. Venus! surely it is scarcely beautiful enough for
that.

#. But they had disposed of the most beautiful ones
before. Iron is Mars.

ff, That is right enough, becauso swords are made
of iron.

Z. True. Then tin is Jupiter, and lead Saturn.
The dulness of lead might be thought to agree with
that planet whichis most remote from the sun. These |
names, childish as they may seem, are worth remem-
bering, since chemists and physicians still apply them
to many preparations of the various metals. You will
probably often hear of martial, lunar, mercurial, and
saturmne ; and you may now know what they mean.

G. I think the knowledge of metals seems more
useful than all you have told us about plants.

T. I don’t know that. Many nations make no use
at all of metals, but there are none which do not owe
a great part of their subsistence to vegetables. How-
ever, without inquiring what parts of natural knowledge
are most useful, you may be assured of this, that all
are useful in some degree or other; and there are
few things that give one man greater superiority over
another, than the extent and accuracy or his knowledge
in these particulars. One person passes all his life
upon the earth, a stranger to it; while another finds
himself at home everywhere. To what I have already
said respecting metals, may be added, that, of metals
and metallic substances, there are, in the aggregate,
upwards of fifty. Amongst them may be mentioned
antimony, bismuth, arsenic, cobalt, platinum, nickel,
manganese, rhodium, potassium, sodium, magnesium,
vanadium, &e. Of these, many are extensively used
in medicines and in the arts.