Page 62 [62]
34 LIGHT AND WATER
one nearer than D, so that the image would be still
more drawn out.
We are now able to understand the simple method
by which Nature produces this most beautiful effect.
As the plainest possible instance, we can imagine the
picture FG to represent the white side of a house,
the wall below to represent the grassy bank on which
it stands, and the wall above the blue sky. The re¬
flexion of the house is drawn out to twice its natural
height, the green light from the bank mingles with
this for some distance, and the whole is interrupted
by patches of blue sky. [he motion of the water gives
life to the image, increasing thereby its extreme deli¬
cacy both of form and colour. We have supposed the
ripples to be parallel to the bank on which we are
standing, and, indeed, this is usually the case if the
water is not too deep close to its edge, for the waves,
whatever their former direction, on reaching shallow
water veer round and range themselves parallel to
the shore line—so that these interruptions of one part
of the image by another take the form of horizontal
strokes or lines. This is clearly seen in the fore¬
ground of Plate VI; note also the reflexion of the
headland in Plate XX XI, page 66.
Fig. 14 shows how, looking from Q, a luminous
point P may be seen reflected at different points on
the surfaces of succeeding waves. A number of lines,
representing rays of light, are drawn proceeding from
P and hitting the surface of the water, but only those
are shown which after reflexion reach the eye at 0.
If the water were still, P would be seen by reflexion
on the smooth surface at the point X, its image