sclose that
native Yellow, and look rather as if Gold, than if the above mention'd
mixture, had been rubb'd upon the Stone.

[15] See _Scaliger_ Exercit. 325. Sect. 9.

_EXPERIMENT XIV._

I took a piece of Black-horn, (polish'd as being part of a Comb) this with
a piece of broken glass I scrap'd into many thin and curdled flakes, some
shorter and some longer, and having laid a pretty Quantity of these
scrapings together, I found, as I look'd for, that the heap they compos'd
was White, and though, if I laid it upon a clean piece of White Paper, its
Colour seem'd somewhat Eclips'd by the greater Whiteness of the Body it was
compar'd with, looking somewhat like Linnen that had been sulli'd by a
little wearing, yet if I laid it upon a very Black Body, as upon a Beaver
Hatt, it then appear'd to be of a good White, which Experiment, that you
may in a trice make when you please, seems very much to Disfavour both
their Doctrine that would have Colours to flow from the Substantial Forms
of Bodyes, and that of the Chymists also, who ascribe them to one or other
of their three Hypostatical Principles; for though in our Case there was so
great a Change made, that the same Body without being substantially either
Increas'd or Lessened, passes immediately from one extreme Colour to
another (and that too from Black to White) yet this so great and sudden
change is effected by a slight Mechanical Transposition of parts, there
being no Salt or _Sulphur_ or _Mercury_ that can be pretended to be Added
or Taken away, nor yet any substantial Form that can reasonably be suppos'd
to be Generated and Destroy'd, the Effect proceeding only from a Local
Motion of the parts which so vary'd their Position as to multiply their
distinct Surfaces, and to Qualifie them to Reflect far more Light to the
Eye, than they could before they were scrap'd off from the entire piece of
Black horn.

_EXPERIMENT XV._

And now, _Pyrophilus_, it will not be improper for us to take some notice
of an Opinion touching the cause of Blackness, which I judged it not so
seasonable to Question, till I I had set down some of the Experiments, that
might justifie my dissent from it. You know that of late divers Learned
Men, having adopted the three Hypostatical Principles, besides other
Notions of the Chymists, are very inclinable to reduce all Qualities of
Bodies to one or other of those three Principles, and Particularly assign
for the cause of Blackness the Sootie steam