they are rather (to borrow a terme of the Grammarians) De-compound
Bodies, made up of the whole Metal and the _Menstruum_ or other
Additaments imploy'd to disguise it. And as for Silver, I never could
see any degree of Fire make it part with any of its three Principles.
And though the Experiment lately mentioned from _Claveus_ may beget a
Suspition that Silver may be dissipated by Fire, provided it be
extreamly violent and very lasting: yet it will not necessarily
follow, that because the Fire was able at length to make the Silver
lose a little of its weight, it was therefore able to dissipate it
into its Principles. For first I might alledge that I have observ'd
little Grains of Silver to lie hid in the small Cavities (perhaps
glas'd over by a vitrifying heat) in Crucibles, wherein Silver has
been long kept in Fusion, whence some Goldsmiths of my Acquaintance
make a Benefit by grinding such Crucibles to powder, to recover out of
them the latent particles of Silver. And hence I might argue, that
perhaps _Claveus_ was mistaken, and imagin'd that Silver to have been
driven away by the Fire, that indeed lay in minute parts hid in his
Crucible, in whose pores so small a quantity as he mist of so
ponderous a Bodie might very well lie conceal'd.
But Secondly, admitting that some parts of the Silver were driven away
by the violence of the Fire, what proof is there that it was either
the Salt, the Sulphur, or the Mercury of the Metal, and not rather a
part of it homogeneous to what remain'd? For besides, that the Silver
that was left seem'd not sensibly alter'd, which probably would have
appear'd, had so much of any one of its Principles been separated from
it: We finde in other Mineral Bodies of a less permanent nature than
Silver, that the Fire may divide them into such minute parts, as to be
able to carry them away with its self, without at all destroying their
Nature. Thus we see that in the refining of Silver, the Lead that is
mix'd with it (to carry away the Copper or other ignoble Mineral that
embases the Silver) will, if it be let alone, in time evaporate away
upon the Test; but if (as is most usual amongst those that refine
great quantities of Metals together) the Lead be blown off from the
Silver by Bellowes, that which would else have gone away in the Form
of unheeded steams, will in great part be collected not far from the
Silver, in the Form of a darkish Powder or Calx, which, because it is
blown off from Silver, they call Litharge of Silver. And thus
_Agricola_[3] in divers places informs us, when Copper, or the Oare of
it is colliquated by the violence of the Fire with _Cadmia_, the
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