inform'd us what kinde of Division of Bodies by Fire must determine
the number of the Elements: For it is nothing near so easy as many
seem to think, to determine distinctly the Effects of Heat, as I could
easily manifest, if I had leasure to shew you how much the Operations
of Fire may be diversify'd by Circumstances. But not wholly to pass by
a matter of this Importance, I will first take notice to you, that
_Guajacum_ (for Instance) burnt with an open Fire in a Chimney, is
sequestred into Ashes and Soot, whereas the same Wood distill'd in a
Retort does yield far other Heterogeneities, (to use the _Helmontian_
expression) and is resolv'd into Oyl, Spirit, Vinager, Water and
Charcoal; the last of which to be reduc'd into Ashes, requires the
being farther calcin'd then it can be in a close Vessel: Besides
having kindled Amber, and held a clean Silver Spoon, or some other
Concave and smooth Vessel over the Smoak of its Flame, I observ'd the
Soot into which that Fume condens'd, to be very differing from any
thing that I had observ'd to proceed from the steam of Amber purposely
(for that is not usual) distilled _per se_ in close Vessels. Thus
having, for Tryals sake, kindled Camphire, and catcht the Smoak that
copiously ascended out of the Flame, it condens'd into a Black and
unctuous Soot, which would not have been guess'd by the Smell or other
Properties to have proceeded from Camphire: whereas having (as I shall
otherwhere more fully declare) expos'd a quantity of that Fugitive
Concrete to a gentle heat in a close Glass-Vessel, it sublim'd up
without seeming to have lost any thing of its whiteness, or its
Nature, both which it retain'd, though afterwards I so encreased the
Fire as to bring it to Fusion. And, besides Camphire, there are divers
other Bodies (that I elsewhere name) in which the heat in close
Vessels is not wont to make any separation of Heterogeneities, but
only a comminution of Parts, those that rise first being Homogeneal
with the others, though subdivided into smaller Particles: whence
Sublimations have been stiled, _The Pestles of the Chymists_. But not
here to mention what I elsewhere take notice of, concerning common
Brimstone once or twice sublim'd, that expos'd to a moderate Fire in
Subliming-Pots, it rises all into dry, and almost tastless, Flowers;
Whereas being expos'd to a naked Fire it affords store of a Saline and
Fretting Liquor: Not to mention this, I say, I will further observe to
you, that as it is considerable in the _Analysis_ of mixt Bodies,
whether the Fire act on them when they are expos'd to the open Air, or
shut up in close Vessels, so is the degree of Fire by which the
_Analysis_ is attempted of no small moment. For a milde _Balneum_ will
34