ng seen {126} some stones
reputed to be _natural_ that had most lively Pictures, not only upon them,
but passing _thorow_ their whole substance, and thereupon finding an
_Artist_; skilful to perform such rare workmanship, did not only pronounce
such stones to be _artificial_, but when that _Artist_ was unwilling to
communicate unto him his Secret, did joyn his study and endeavors with
those of one _Albertus Gunter_ a _Saxon_, to find it out themselves:
wherein having succeeded, it seems, they made the Experiments which this
Industrious and communicative _Jesuit_ delivers in this manner:

The Colours, saith he, are thus prepared; I take of _Aqua fortis_ and _Aqua
Regis_, two ounces _ana_; of _Sal Armoniack_ one ounce; of the best _Spirit
of Wine_, two drachms; as much _Gold_ as can be had for nine _Julio_'s (a
_Julio_ being about six pence English) of pure _Silver_, two drachmes.
These things being provided, let the Silver, when calcined, be put into a
Vial; and having powred upon it the two drachmes of _Aqua fortis_, let it
evaporate, and you shall have a Water yielding first a _blew_ Colour, and
afterwards a _black_. Likewise put the Gold, when calcin'd, into a Vial,
and having powred the _Aqua Regis_ upon it, set it by to evaporate: then
put the _Spirit of Wine_ upon the _Sal Armoniack_, leaving it also till it
be evaporated; and you will have a Golden coloured Water, which will afford
you divers Colours. And, after this manner, you may extract many
_Tinctures_ of Colours out of other Mettals. This done, you may, by the
means of these two Waters, paint what Picture you please upon white Marble,
of the _softer_ kind, renewing the Figure every day for several days with
some fresh superadded Liquor, and you shall find in time, that the Picture
hath penetrated the _whole_ solidity of the Stone, so that cutting it into
as many parts as you will, it will always represent unto you the same
Figure on both sides.

_So far he_, which how far it answers expectation, is referred to the Tryal
of Ingenious Artists. In the mean time there are not wanting Experienced
Men that scruple the Effect, but {127} yet are far from pronouncing any
thing positively against it, so that they doe not discourage any that have
conveniencies, from trying.

But whether the way there mentioned will succeed, or not, according to
expectation: Sure it is that a Stone-cutter in _Oxford_, Mr. _Bird_, hath
many years since found out a way of doing the same