And next, that we have our selves made Glasses not
unfit to exhibit an Experiment not unlike that I have been speaking of, by
laying upon pieces of Glass some very finely foliated Silver, and giving it
by degrees a much stronger Fire than is requisite or usual for the Tinging
of Glasses of other Colours. And this Experiment, not to mention that it
was made without a Furnace in which Artificers that Paint Glass are wont to
be very Curious, is the more considerable, because, that though a Skilfull
Painter could not deny to me that 'twas with Silver he Colour'd his Glasses
Yellow; yet he told me, that when to Burn them (as they speak) he layes on
the plates of Glass nothing but a _Calx_ of Silver Calcin'd without
Corrosive Liquors, and Temper'd with Fair Water, the Plates are Ting'd of a
fine Yellow that looks of a Golden Colour, which part soever of it you turn
to or from the Light; whereas (whether it be what an Artificer would call
Over-doing, or Burning, or else the imploying the Silver Crude that makes
the Difference,) we have found more than once, that some Pieces of Glass
prepar'd as we have related, though held against the Light they appear'd of
a Transparent Yellow, yet look'd on with ones back turn'd to the Light they
exhibited an Untransparent Blew.
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