_Exper._ 6. And as these Colours were not changeable by Refractions, so
neither were they by Reflexions. For all white, grey, red, yellow,
green, blue, violet Bodies, as Paper, Ashes, red Lead, Orpiment, Indico
Bise, Gold, Silver, Copper, Grass, blue Flowers, Violets, Bubbles of
Water tinged with various Colours, Peacock's Feathers, the Tincture of
_Lignum Nephriticum_, and such-like, in red homogeneal Light appeared
totally red, in blue Light totally blue, in green Light totally green,
and so of other Colours. In the homogeneal Light of any Colour they all
appeared totally of that same Colour, with this only Difference, that
some of them reflected that Light more strongly, others more faintly. I
never yet found any Body, which by reflecting homogeneal Light could
sensibly change its Colour.
From all which it is manifest, that if the Sun's Light consisted of but
one sort of Rays, there would be but one Colour in the whole World, nor
would it be possible to produce any new Colour by Reflexions and
Refractions, and by consequence that the variety of Colours depends upon
the Composition of Light.
_DEFINITION._
The homogeneal Light and Rays which appear red, or rather make Objects
appear so, I call Rubrifick or Red-making; those which make Objects
appear yellow, green, blue, and violet, I call Yellow-making,
Green-making, Blue-making, Violet-making, and so of the rest. And if at
any time I speak of Light and Rays as coloured or endued with Colours, I
would be understood to speak not philosophically and properly, but
grossly, and accordingly to such Conceptions as vulgar People in seeing
all these Experiments would be apt to frame. For the Rays to speak
properly are not coloured. In them there is nothing else than a certain
Power and Disposition to stir up a Sensation of this or that Colour.
For as Sound in a Bell or musical String, or other sounding Body, is
nothing but a trembling Motion, and in the Air nothing but that Motion
propagated from the Object, and in the Sensorium 'tis a Sense of that
Motion under the Form of Sound; so Colours in the Object are nothing but
a Disposition to reflect this or that sort of Rays more copiously than
the rest; in the Rays they are nothing but their Dispositions to
propagate this or that Motion into the Sensorium, and in the Sensorium
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