de seipso refert, tam mutati Coloris, quam à casu preservationis. Cui &
ipse haud dissimile adferre possum, nisi ex Anshelmo petitum quis putaret._
I remember that I saw two or three years since a _Turcois_ (worn in a Ring)
wherein there were some small spots, which the _Virtuoso_ whose it was
asur'd me he had observ'd to grow sometimes greater sometimes less, and to
be sometimes in one part of the Stone, sometimes in another. And I having
encourag'd to make Pictures from time to time of the Stone, and of the
Situation of the cloudy parts, thatso their Motion may be more
indisputable, and better observ'd, he came to me about the midle of this
very week, and assur'd me that he had, as I wish'd, made from time to time
Schemes or Pictures of the differing parts of the Stone, whereby the
several Removes and motions of the above mentioned Clouds are very
manifest, though the cause seem'd to him very occult: these Pictures he has
promis'd to show me, and is very ready to put the Stone it self into my
hands. But the ring having been the other day casually broken upon his
finger, unless it can be taken out, and set again without any considerable
heat, he is loath to have it medled with, for fear its peculiarity should
be thereby destroy'd. And possibly his apprehension would have been
strengthen'd, if I had had opportunity to tell him what is related by the
Learned _Wormius_[33] of an acquaintance of his, that had a _Nephritick_
stone, of whose eminent Virtues he had often Experience ev'n in himself,
and for that cause wore it still about his Wrist; and yet going upon a time
into a Bath of fair Water only, wherein certain Herbs had been boyl'd, the
Stone by being wetted with this decoction, was depriv'd of all his Virtue,
whence _Wormius_ takes Occasion to advertise the sick, to lay by such
stones whensoever they make use of a Bath. 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