ilosophy, has, though but Incidentally, deliver'd something
towards the Explication of Whiteness upon Mechanical Principles: And
because no Man that I know of, has done so before him, I shall, to be sure
to do him Right, give you his Sense in his own Words:[7] _Cogites velim_
(says he) _lucem quidem in Diaphano nullius coloris videri, sed in Opaco
tamen terminante Candicare, ac tanto magis, quanto densior seu collectior
fuerit. Deinde aquam non esse quidem coloris ex se candidi & radium tamen
ex ea reflexum versus oculum candicare. Rursus cum plana aquae Superficies
non nisi ex una parte eam reflexionem faciat: si contigerit tamen illam in
aliquot bullas intumescere, bullam unamquamque reflectionem facere, &
candoris speciem creare certa Superficiei parte. Ad haec Spumam ex aqua pura
non alia ratione videri candescere & albescerere quam quod sit congeries
confertissima minutissimarum bullarum, quarum unaquaeque suum radium
reflectit, unde continens candor alborve apparet. Denique Nivem nihil aliud
videri quam speciem purissimae spumae ex bullulis quam minutissimis &
confertissimis cohaerentis. Sed ridiculam me exhibeam, si tales meas nugas
uberius proponem._

[6] _Album quippe & agrum, hoc quidem asperum esse dicit, hoc vero laeve.
de Sensu & Sensib. 3. 3._

[7] Epist. 2. pag. 45.

3. But though in this passage, that very Ingenous Person has Anticipated
part of what I should say; Yet I presume you will for all that expect, that
I should give you a fuller Account of that Notion of Whiteness, which I
have the least Exceptions to, and of the Particulars whence I deduce it,
which to do, I must mention to you the following Experiments and
Observations.

Whiteness then consider'd as a Quality in the Object, seems chiefly to
depend upon this, That the Superficies of the Body that is call'd White, is
Asperated by almost innumerable Small Surfaces, which being of an almost
Specular Nature, are also so Plac'd, that some Looking this way, and some
that way, they yet Reflect the Rays of Light that fall on them, not towards
one another, but outwards towards the Spectators Eye. In this Rude and
General account of Whiteness, it seems that besides those Qualities, which
are common to Bodies of other Colours, as for instance the Minuteness and
Number of the Superficial parts, the two chief things attributed to Bodies
as White are made to be, First, that its Little Protuberances and
Superficial parts be of somewhat a Specular Na