And we might expect to find
_Turcos_ likewise, easily to be wrought upon in point of Colour, if that
were true, which the curious _Antonio Neri_, in his ingenious _Arte
Vetraria_[34] teaches of it, namely, That _Turcois's discolour'd_ and grown
white, will regain and acquire an excellent Colour, if you but keep them
two or three days at most cover'd with Oyl of sweet Almonds kept in a
temperate heat by warm ashes, I say if it were true, because I doubt
whether it be so, and have not as yet had opportunity to satisfie my self
by Tryals, because I find by the confession of the most Skilfull Persons
among whom I have laid out for _Turcoises_, that the true ones are great
rarities, though others be not at all so. And therefore I shall now only
mind you of one thing that you know as well as I, namely, that the rare
Stone which is called _Oculus Mundi_, if it be good in its Kind, will have
so great a change made in its Texture by being barely left a while in the
Languidest of Liquors, common Waters, that from Opacous it will become
Transparent, and acquire a Lustre of which it will again be depriv'd,
without using any other Art or Violence, by leaving it a while in the Air.
And before experience had satisfy'd us of the truth of this, it seem'd as
unlikely that common Water or Air, should work such great changes in that
Gemm, as it now seems that the Effluviums of a human Body should effect
lesser changes in a _Turcois_, especially if more susceptible of them, than
other Stones of the same kind.
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