ut if you Prosecute the
Calcination, this Body which by a light Adustion was made White, will pass
through other Colours, as Gray, Yellowish, and Red; and if you further burn
it with a Long and Vehement fire, by that time it comes to be _Perustum_,
it will be of a dark purple, nearer to Black, not only than the first
_Calx_, but than the Vitriol before it at all felt the fire. I might add
that _Crocus_ _Martis_ (_per se_ as they call it) made by the Lasting
violence of the Reverberated flames is not so near a Kin to White, as the
Iron or Steel that afforded it was before its Calcinations; but that I
suppose, these Instances may Suffice to satisfie you, that Minerals are to
be excepted out of the forementioned Rule, which perhaps, though it seldome
fail in substances belonging to the Vegetable or Animal Kingdome, may yet
be Question'd even in some of these, if that be true, which the Judicious
Traveller _Bellonius_ affirms, that Charcoales made out of the Wood of
_Oxycaeder_ are White; And I could not find that though in Retorts Hartshorn
and other White Bodies will be Denigrated by Heat, yet Camphire would not
at all lose its Whiteness, though I have purposely kept it in such a heat,
as made it melt and boyl.

_EXPERIMENT V._

And now I speak of Camphire, it puts me in mind of adding this Experiment,
That, though as I said in Clos'd Glasses, I could not Denigrate it by Heat,
but it would Sublime to the sides and top of the Glass, as it was before,
yet not only it will, being set on fire in the Free Air, send forth a
Copious smoak, but having purposely upon some of it that was Flaming, clapt
a Large Glass, almost in the form of a Hive, (but more Slender only) with a
Hole at the top, (which I caus'd to be made to trye Experiments of Fire and
Flame in) it continued so long burning that it Lin'd all the Inside of the
Glass with a Soot as Black as Ink, and so Copious, that the Closeness of
the Vessel consider'd, almost all that part of the White Camphire that did
take Fire, seem'd to have been chang'd into that deep Black Substance.

_EXPERIMENT VI_

And this also brings into my mind another Experiment that I made about the
production of Blackness, whereof, for Reasons too long to be here deduced,
I expected and found a good Success, an it was this: I took Rectifi'd Oyl
of Vitriol (that I might have the Liquor Clean as well as Strong) and by
degrees mixt with it a convenient proportion of the Essential Oyl, as
Chymists ca