Stranica 140 [140]
78 LIGHT AND WATER
when, as is often the case after stormy weather, the
sea assumes an almost milky appearance owing to
the great quantity of minute particles of chalk float¬
ing in the water, the shadows cast by passing clouds
are very conspicuous.
As the local colour is revealed by strong illumina¬
tion from above, so it loses in proportion as the re¬
flexions with which it has to contend, are themselves
brilliant. Everyone is familiar with the difficulty of
seeing objects in the dusk through the closed window
of a well-lighted room, until a blind or curtain has
been drawn to cut off the bright reflexions on the
window-pane; and, in the same way, strong reflexions
on the surface of water prevent us from seeing be¬
neath the surface. We have observed that, if the sun
is hidden, the colour of the water near us is often
barely perceptible; and this is in great measure due
. to the fact that the reflexion-picture here consists (in
all probability) of blue sky or highly luminous clouds;
and we also found that the colour of the water was
most apparent in the reflexions of the trees, for the
reflexion-picture there being dark or feebly illumin¬
ated, the colour of the water had again a chance to
show itself. Hence the explanation of the well-known
fact that it is in the reflexions of dark objects, such
as heavy foliage or the tarred side of a boat, that we
most clearly perceive the colour of water.’ This fact
is often expressed by saying that bright objects are
reflected in their natural colours, whilst those that
are very dark appear the colour of the water—a say¬
’ Or, if the water be very shallow, that the bottom is most plainly
visible.