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Boyle, Robert, 1627-1691

"Experiments and Considerations Touching Colours (1664)"


2. And this Texture may be Explicated two, and perhaps more than two
several ways, whereof the first is by Supposing in the Superficies of the
Black Body a Particular kind of Asperity, whereby the Superficial Particles
reflect but Few of the Incident Beams Outwards, and the rest Inwards
towards the Body it self. As if for Instance, we should conceive the
Surface of a Black Body to be Asperated by an almost Numberless throng of
Little Cylinders, Pyramids, Cones, and other such Corpuscles, which by
their being Thick Set and _Erected_, reflect the Beams of Light from one to
another Inwards, and send them too and fro so often, that at length they
are Lost before they can come to Rebound out again to the Eye. And this is
the first of the two mention'd ways of Explicating Blackness. The other way
is by Supposing the Texture of Black Bodies to be such, that either by
their Yielding to the Beams of Light, or upon some other Account, they do
as it were Dead the Beams of Light, and keep them from being Reflected in
any Plenty, or with any Considerable Vigour of Motion, Outwards. According
to this Notion it may be said, that the Corpuscles that make up the Beams
of Light, whether they be Solary _Effluviums_, or Minute Particles of some
AEtherial Substance, Thrusting on one another from the Lucid Body, do,
falling on Black Bodies, meet with such a Texture, that such Bodies receive
Into themselves, and Retain almost all the Motion communicated to them by
the Corpuscles that make up the Beams of Light, and consequently Reflect
but Few of them, or those but Languidly, towards the Eye, it happening here
almost in like manner as to a ball, which thrown against a Stone or Floor,
would Rebound a great way Upwards, but Rebounds very Little or not at all,
when it is thrown against Water, or Mud, or a Loose Net, because the Parts
yield, and receive into themselves the Motion, on whose Account the Ball
should be Reflected Outwards.


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