that I have heard the Author express himself,
that it would not surprise him, if it should happen to be objected, that
some of these Experiments have been already published, partly by Chymists,
and partly by two or three very fresh Writers upon other Subjects. And
though the number of these Experiments be but very small, and though they
be none of the considerablest, yet it may on this occasion be further
represented, that it is easie for our Author to name several men, (of whose
number I can truly name my self) who remember either their having seen him
make, or their having read, his Accounts of the Experiments delivered in
the following Tract several years since, and long before the publication of
the Books, wherein they are mentioned. Nay in divers passages (where he
could do it without any great inconvenience) he hath struck out
Experiments, which he had tryed many years ago, because he since found them
divulged by persons from whom he had not the least hint of them; which yet
is not touched, with design to reflect upon any Ingenious Man, as if he
were a Plagiary: For, though our Generous Author were not reserved enough
in showing his Experiments to those that expressed a Curiosity to see them
(amongst whom a very Learned Man hath been pleased publickly to acknowledge
it several years ago[2]; yet the same thing may be well enough lighted on
by persons that know nothing of one another. And especially Chymical
Laboratories may many times afford the same _Phaenomenon_ about Colours to
several persons at the same or differing times. And as for the few
_Phaenomena_ mentioned in the same Chymical writers, as well as in the
following Treatise, our Author hath given an account, why he did not
decline rejecting them, in the Anotations upon the 47th Experiment of the
third part. Not here to mention, what he elsewhere saith, to shew what use
may be Justifiably made of Experiments not of his own devising by a writer
of Natural History, if, what he employes of others mens, be well examined
or verified by himself.

[2] He that desires more instances of this kind and matter, that
according to this doctrine may much help the Theory of colours, and
particularly the force both of Sulphureous and volatile, is likewise of
Alcalizate and Acid Salts, and in what particulars, Colours likely depend
not in the causation from any Salt at all, may beg his information from
M. Boyle who hath some while since honoured me with the sight