who makes such Colour'd Glass told me, that where as the Red Pigment was
but Superficial, the Yellow penetrated to the very midst of the Plate. But
for further Satisfaction, not having the Opportunity to Foliate those
Plates, and so turn them into Looking-glasses, we Foliated a Plate of
_Muscovy_ Glass, and then laying on it a little Transparent Varnish of a
Gold Colour, we expos'd it to the Sun-beams, so as to cast them upon a Body
fit to receive them, on which the Reflected Light, appearing, as we
expected, Yellow, manifested that Rebounding from the Specular part of the
_Selenitis_, it was Ting'd in its return with the Colour of the Transparent
Varnish through which it pass'd.

_EXPERIMENT XIV._

After what we have said of the Composition of Colours, it will now be
seasonable to annex some Experiments that we made in favour of those
Colours, that are taught in the Schools not to be Real, but only Apparent
and Phantastical; For we found by Tryals, that these Colours might be
Compounded, both with True and Stable Colours, and with one another, as
well as unquestionably Genuine and Lasting Colours, and that the Colours
resulting from such Compositions, would respectively deserve the same
Denominations.

For first, having by the Trajection of the Sun-beams through a Glass-prism
thrown an Iris on the Floor, I found that by placing a Blew Glass at a
convenient distance betwixt the Prism and the Iris, that part of the Iris
that was before Yellow, might be made to appear Green, though not of a
Grass Green, but of one more Dilute and Yellowish. And it seems not
improbable, that the narrow Greenish List (if I may so call it) that is
wont to be seen between the Yellow and Blew parts of the Iris, is made by
the Confusion of those two Bordering Colours.