s with. And if the Superficial Corpuscles be of the Grosser sort,
and be so Framed, that their differing Sides or Faces may exhibit differing
Colours, then the Motion or Rest of those Corpuscles may be considerable,
as to the Colour of the Superficies they compose, upon this account, that
sometimes more, sometimes fewer of the Sides dispos'd to exhibit such a
Colour may by this means become or continue more Obverted to the Eye than
the rest, and compose a Physical Surface, that will be more or less
sensibly interrupted; As, to explane my meaning, by proposing a gross
Example, I remember, that in some sorts of Leavy Plants thick set by one
another, the two sides of whose Leaves were of somewhat differing Colours,
there would be a notable Disparity as to Colour, if you look'd upon them
both when the Leaves being at Rest had their upper and commonly expos'd
sides Obverted to the Eye, and when a breath of Wind passing thorow them,
made great Numbers of the usually Hidden sides of the Leaves become
conspicuous. And though the Little Bodies, we were lately speaking of, may
Singly and Apart seem almost Colourless, yet when Many of them are plac'd
by one another, so near, that the Eye does not easily discern an
Interruption, within a sensible space, they may exhibit a Colour; as we
see, that though a Slenderest Thrid of Dy'd Silk do's, whilst look'd on
Single, seem almost quite Devoyd of Redness, (for instance) yet when
numbers of these Thrids are brought together into one Skein, their Colour
becomes notorious.

9. But the same Occasion that invited me to say what I have mention'd
concerning the Leaves of Trees, invites me also to give you some account of
what happens in Changeable Taffities, where we see differing Colours, as it
were, Emerge and Vanish upon the Ruffling of the same piece of Silk: As I
have divers times with Pleasure observ'd, by the help of such a
_Microscope_, as, though it do not very much Magnifie the Object, has in
recompence this great Conveniency, that you may easily, as fast as you
please, remove it from one part to another of a Large Object, of which the
Glass taking a great part at once, you may thereby presently Survey the
Whole. Now by the help of such a _Microscope_ I could easily (as I began to
say) discern, that in a piece of Changeable Taffity, (that appear'd, for
Instance, sometimes Red, and sometimes Green) the Stuff was compos'd of Red
thrids and Green, passing under and over each other, and cr