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.

Next, I found, that though the want of a sufficient Liveliness in either of
the Compounding Colours, or a light Error in the manner of making the
following Tryals, was enough to render some of them Unsuccessfull, yet when
all necessary Circumstances were duely observ'd, the Event was answerable
to our Expectation and Desire.

And (as I formerly Noted) that Red and Blew compound a Purple, so I could
produce this last nam'd Colour, by casting at some Distance from the Glass
the Blew part of the Prismatical Iris (as I think it may be call'd for
Distinction sake) upon a Lively Red, (for else the Experiment succeeds not
so well.) And I remember, that sometimes when I try'd this upon a piece of
Red Cloath, _that_ part of the Iris which would have been Blew, (as I try'd
by covering that part of the Cloath with a piece of White Paper) and
Compounded with the Red, wherewith the Cloath was Imbued before, appear'd
of a fair Purple, did, when I came to View it near at hand, look very Odly,
as if there were some strange Reflection or Refraction or both made in the
Hairs of which that Cloath was composed.

Calling likewise the Prismatical Iris upon a very Vivid Blew, I found that
part of it, which would else have been the Yellow, appear Green. (Another
somewhat differing Tryal, and yet fit to confirm this, you will find in the
fifteenth Experiment.)

But it may seem somewhat more strange, that though the Prismatical Iris
being made by the Refraction of Light through a Body that has no Colour at
all, must according to the Doctrine of the Schools consist of as purely
Emphatical Colours, as may be, yet even these may be Compounded with one
another, as well as Real Colours in the Grossest Pigments. For I took at
once two Triangular Glasses, and one of them being kept fixt in the same
Posture, that the Iris it projected on the Floor might not Waver, I cast on
the same Floor another Iris with the other Prism, and Moving it too and fro
to bring what part of the second Iris I pleas'd, to fall upon what part of
the first I thought fit, we did sometimes (for a small Errour suffices to
hinder the Success) obtain by this means a Green Colour in that part of the
more Stable Iris, that before was Yellow, or Blew, and frequently by
casting those Beams