But because all those _opacous_ colours have two kinds of beams or Rays
reflected from them, that is, Rays unting'd, which are onely reflected from
the outward surface, without at all penetrating of the body, and ting'd
Rays which are reflected from the inward surfaces or flaws after they have
suffer'd a two-fold refraction; and because that transparent liquors mixt
with such _corpuscles_, do, for the most part, take off the former kind of
reflection; therefore these colours mixt with Water or Oyl, appear much
deeper than when dry, for most part of that white reflection from the
outward surface is remov'd. Nay, some of these colours are very much
deepned by the mixture with some transparent liquor, and that because they
may perhaps get between those two flaws, and so consequently joyn two or
more of those flaw'd pieces together; but this happens but in a very few.
Now, to shew that all this is not _gratis dictum_, I shall set down some
Experiments which do manifest these things to be probable and likely, which
I have here deliver'd.
For, first, if you take any ting'd liquor whatsoever, especially if it be
pretty deeply ting'd, and by any means work it into a froth, the
_congeries_ of that froth shall seem an _opacous_ body, and appear of the
same colour, but much whiter than that of the liquor out of which it is
made. For the abundance of reflections of the Rays against those surfaces
of the bubbles of which the froth consists, does so often rebound the Rays
backwards, that little or no light can pass through, and consequently the
froth appears _opacous_.
Pages:
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213