Wherefore to try the Composition of
Colours by Trajection, we provided several Plates of Tinged Glass, which
being laid two at a time one on the top of another, the Object look'd upon
through them both, appear'd of a Compounded Colour, which agrees well with
what we have observ'd in the second Experiment, of Looking against the
Light through differingly Colour'd Papers. But we thought the Experiment
would be more Satisfactory, if we procur'd the Sun-beams to be so Ting'd in
their passage through Plates of Glass, as to exhibit the Compounded Colour
upon a Sheet of White Paper. And though by reason of the Thickness of the
Glasses, the Effect was but Faint, even when the Sun was High and Shin'd
forth clear, yet, we easily remedied that by Contracting the Beams we cast
on them by means of a Convex Burning-glass, which where it made the Beams
much converge Increas'd the Light enough to make the Compounded Colour very
manifest upon the Paper. By this means we observ'd, that the Beams
trajected through Blew and Yellow compos'd a Green, that an intense and
moderate Red did with Yellow make differing degrees of Saffron, and Orange
Tawny Colours, that Green and Blew made a Colour partaking of both, such as
that which some Latin Writers call _Pavonaceus_, that Red and Blew made a
Purple, to which we might add other Colours, that we produc'd by the
Combinations of Glasses differingly Ting'd, but that I want proper Words to
express them in our Language, and had not when we made the Tryals, the
Opportunity of consulting with a Painter, who perchance might have Suppli'd
me with some of the terms I wanted.
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