9. I know not whether I should on this Occasion take notice, that when, as
when looking upon the Calm and Smooth Surface of a River betwixt my Eye and
the Sun, it appear'd to be a natural _Speculum_, wherein that Part which
Reflected to my Eye the Entire and defin'd Image of the Sun, and the Beams
less remote from those which exhibited That Image, appear'd indeed of a
great and Whitish Brightness, but the rest Comparatively Dark enough: if
afterwards the Superficies chanc'd to be a little, but not much troubled,
by a gentle Breath of Wind, and thereby reduc'd into a Multitude of Small
and Smooth _Speculums_, the Surface of the River would suitably to the
Doctrine lately deliver'd, at a Distance appear very much of Kin to White,
though it would lose that Brightness or Whiteness upon the Return of the
Surface to Calmness and an Uniform Level. And I have sometimes for Tryals
sake brought in by a Lenticular Glass, the Image of a River, Shin'd upon by
the Sun, into an Upper Room Darkn'd, and Distant about a Quarter of a Mile
from the River, by which means the Numerous Declining Surfaces of the Water
appear'd so Contracted, that upon the Body that receiv'd the Images, the
whole River appear'd a very White Object at two or three paces distance.
But if we drew Near it, this Whiteness appear'd to proceed from an
Innumerable company of Lucid Reflections, from the several Gently wav'd
Superficies of the Water, which look'd Near at hand like a Multitude of
very Little, but Shining Scales of Fish, of which many did every moment
Disappear, and as many were by the Sun, Wind and River generated anew. But
though this Observation seem'd Sufficiently to discover, how the Appearing
Whiteness in that case was Produc'd, yet in some other cases Water may have
the Same, though not so Vivid a Colour upon other Accounts; for oftentimes
it happens that the Smooth Surface of the Water does appear Bright or
Whitish, by reason of the Reflection not immediatly of the Images of the
Sun, but of the Brightness of the Sky; and in such cases a Convenient Wind
may where it passes along make the Surface look Black, by causing many such