Though several Persons have pretended to know the Art of preparing and
calcining the _Bononian_ Stone, for keeping a while the Light once imbibed;
yet there hath been indeed but one, who had the true secret of performing
it. This was an _Ecclesiastick_, who is now dead, without having left that
skill of his to any one, as Letters from _Italy_ and _France_, some while
since, did inform. There is no substance, in Nature, known to us, that hath
the effect of this Stone; so that (to the shame of the present Age) this
_Phaenomenon_ is not like to be found any where, but in Books, except some
happy _Genius_ light upon same or the like skill. *

* * * * *

_A Description of a _Swedish_ Stone, which affords _Sulphur_, _Vitriol_,
_Allum_ and _Minium_._

This was communicated to the _R. Society_ by Sir _Gilbert Talbot_ Knight, a
Worthy Member of that Body, as he had received it in _Denmark_, being his
Majesties Extraordinary Envoy there; as follows,

[Illustration]

There is a Stone in _Sweden_ of a Yellow Colour, intermixed with streaks of
white (as if composed of Gold and Silver) and heavy withal. It is found in
firm Rocks, and runs in Veins, {376} upon which they lay Wood, and set it
on fire. When the Stone is thus heated, they cast Water upon it, to make it
rend, and then dig it up with Mattocks. This done, they break it into
smaller pieces; and put it into Iron-pots, of the shape represented by
_Figure_ C; the mouth of the one going into the other. These they place,
the _one_ in the Oven upon an Iron fork sloping, so that, the Stone being
melted, it may run into the _other_, which stands at the mouth of the Oven,
supported upon an Iron. The first running of the Stone is _Sulphur_.

The remainder of the burned Stone is carry'd out, and laid upon a high
Hill, where it lies exposed to the Sun and Air for the space of two years,
and then taketh fire of it self, casting forth a thin blew flame, scarce
discernable in the day time. This being consumed, leaveth a blew dust
behind it; which the Workmen observe, and mark with woodden pins. This they
dig up, and carry into the Work-house, and put it into great Tubs of Water,
where it infuseth 24. hours or more. The Water they afterward boyl in
Kettles, as we do Saltpeter, and put it into cooling Tubs, wherein they
place crosse Sticks, and on them the _Vitriol_ fastens, as Sugar-candy
doth.

The Water, that remains after the extraction of the _Vitr