Oldal 153 [153]
CHAPTER IV
COLOURS IN RIPPLED WATER
b have now arrived at the last division of our
subject, in which we have to take into account
the colour of the water in combination with a zzó$led
surface. We have seen that when—as is usually the
case with rippled water (see page 29)—the line of
vision strikes the near side of a wave, it is tilted up¬
wards from its normal direction, so that where other
objects had before been seen by reflexion in the still
water, the eye now receives for the most part reflected
skylight. And on page 47 it was pointed out how great
a depth of sky affects every part of the rippled water
beneath it. Thus it is evident that the apparent colour
of the water must be very largely influenced by the
general tone of the sky. Though a smooth sea, looked
at obliquely, reflects only a low region of the heavens,
a rough sea reflects all parts up to a high altitude.
And, if in still water on a clear day the lower or paler
sky is visible, in rippled water it will be chiefly the
deeper light of the upper heaven that meets the eye,
with the result that wherever the breeze catches the
surface the reflected blue gains in intensity, making the
rippled water look darker than the smooth. Should
there be black storm-clouds overhead, the water, as
soon as it is ruffled by the rising wind, reflects their