have occasion to take further notice. I also told you not long since, that
if you corrode Quick-silver with Oyl of Vitriol instead of _Aqua-fortis_,
and abstract the _Menstruum_, there will remain a White _Calx_ which by the
Affusion of Fair Water presently turns into a Lemmon Colour. And ev'n the
_Succedaneum_ to a _Menstruum_ may sometimes serve the turn to change the
Colours of a Metal. The lovely Red which Painters call Vermillion, is made
of Mercury, which is of the Colour of Silver, and of Brimstone which is of
Kin to that of Gold, Sublim'd up together in a certain proportion, as is
vulgarly known to Spagyrists.

_EXPERIMENT XLVIII._

The third chief sort of the Adventitious Colours of Metals, is, that which
is produc'd by associating them (especially when Calcin'd) with other
fusible Bodies, and Principally Venice, and other fine Glass devoid of
Colour.

I have formerly given you an Example, whereby it may appear, that a Metal
may impart to Glass a Colour much differing from its own, when I told you,
how with Silver, I had given Glass a lovely Golden Colour. And I shall now
add, that I have Learn'd from one of the Chief Artificers that sells
Painted Glass, that those of his Trade Colour it Yellow with a preparation
of the _Calx_ of Silver. Though having lately had occasion among other
Tryals to mingle a few grains of Shell-silver (such as is imploy'd with the
Pensil and Pen) with a convenient proportion of powder'd Crystal Glass,
having kept them two or three hours in fusion, I was surpriz'd to find the
Colliquated Mass to appear upon breaking the Crucible of a lovely Saphirine
Blew, which made me suspect my Servant might have brought me a wrong
Crucible, but he constantly affirm'd it to be the same wherein the Silver
was put, and considerable Circumstances countenanc'd his Assertion, so that