out of the candent Vessel into the open Air, the burning Coals did
hastily degenerate or fall asunder, without the Assistance of any new
Calcination, into pure white Ashes. And to these two I shall add but
this obvious and known Observation, that common Sulphur (if it be pure
and freed from its Vinager) being leasurely sublim'd in close Vessels,
rises into dry Flowers, which may be presently melted into a Bodie of
the same Nature with that which afforded them. Though if Brimstone be
burnt in the open Air it gives, you know, a penetrating Fume, which
being caught in a Glass-Bell condenses into that acid Liquor called
Oyl of Sulphur _per Campanam_. The use I would make of these
Experiments collated with what I lately told you out of _Agricola_ is
this, That even among the Bodies that are not fixt, there are divers
of such a Texture, that it will be hard to make it appear, how the
Fire, as Chymists are wont to imploy it, can resolve them into
Elementary Substances. For some Bodies being of such a Texture that
the Fire can drive them into the cooler and less hot part of the
Vessels wherein they are included, and if need be, remove them from
place to place to fly the greatest heat, more easily than it can
divorce their Elements (especially without the Assistance of the Air)
we see that our Chymists cannot Analyze them in close Vessels, and of
other compound Bodies the open Fire can as little separate the
Elements. For what can a naked Fire do to Analyze a mixt Bodie, if its
component Principles be so minute, and so strictly united, that the
Corpuscles of it need less heat to carry them up, than is requisite to
divide them into their Principles. So that of some Bodies the Fire
cannot in close Vessels make any _Analysis_ at all, and others will in
the open Air fly away in the Forms of Flowers or Liquors, before the
Heat can prove able to divide them into their Principles. And this may
hold, whether the various similar parts of a Concrete be combin'd by
Nature or by Art; For in factitious _Sal Armoniack_ we finde the
common and the Urinous Salts so well mingled, that both in the open
Fire, and in subliming Vessels they rise together as one Salt, which
seems in such Vessels irresoluble by Fire alone. For I can shew you
_Sal Armoniack_ which after the ninth Sublimation does still retain
its compounded Nature. And indeed I scarce know any one Mineral, from
which by Fire alone Chymists are wont to sever any Substance simple
enough to deserve the name of an Element or Principle. For though out
of native Cinnaber they distill Quicksilver, and though from many of
those Stones that the Ancients called _Pyrites_ they sublime
Brimstone, yet both that Quicksilver and this Sulphur being very often
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