And as for Whiteness, I think the general affirmation of its
being so easily Destroy'd or Transmuted by any other Colour, ought not to
be receiv'd without some Cautions and Restrictions. For whereas, according
to what I formerly Noted, Lead is by Calcination turned into that Red
Powder we call _Minium_; And Tin by Calcination reduc'd to a White _Calx_,
the common Putty that is sold and us'd so much in Shops, instead of being,
as it is pretended and ought to be, only the _Calx_ of Tin, is, by the
Artificers that make it, to save the charge of Tin, made, (as some, of
themselves have confess'd, and as I long suspected by the Cheap rate it may
be bought for) but of half Tin and half Lead, if not far more Lead than
Tin, and yet the Putty in spight of so much Lead is a very White Powder,
without disclosing any mixture of _Minium_. And so if you take two parts of
Copper, which is a High-colour'd Metall, to but one of Tin, you may by
Fusion bring them into one Mass, wherein the Whiteness of the Tin is much
more Conspicuous and Predominant than the Reddishness of the Copper. And on
this occasion it may not be Impertinent to mention an Experiment, which I
relate upon the Credit of a very Honest man, whom I purposely enquir'd of
about it, being my self not very fond of making Tryals with _Arsenick_, the
Experiment is this, That if you Colliquate _Arsenick_ and Copper in a due
proportion, the _Arsenick_ will Blanch the Copper both within and without,
which is an Experiment well enough Known; but when I enquir'd, whether or
no this White mixture being skilfully kept a while upon the Cupel would not
let go its _Arsenick_, which made Whiteness its praedominant Colour, and
return to the Reddishness of Copper, I was assur'd of the Affirmative; so
that among Mineral Bodyes, some of those that are White, may be far more
capable, than those I am reasoning with seem to have known, of Eclipsing
others, and of making their Colour Praedominant in Mixtures.
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