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. In further
Confirmation of which may be added, that I remember that I also took a lump
of Silver and Gold melted together, wherein by the AEstimate of a very
Experienced Refiner, there might be about a fourth or third part of Gold,
and yet the Yellow Colour of the Gold was so hid by the White of the
Silver, that the whole Mass appear'd to be but Silver, and when it was
rubb'd upon the Touchstone, an ordinary beholder could scarce have
distinguish'd it from the Touch of common Silver; though if I put a little
_Aqua Fortis_ upon any part of the White Surface it had given the
Touchstone, the Silver in the moistned part being immediately taken up and
conceal'd by the Liquor, the Golden Particles would presently di