on which the whole
sentiment and intention of the picture in a great degree depends; but
invariably presenting some new instance of varied knowledge and
observation, some fresh appeal to the highest faculties of the mind.

Sec. 16. Turner's painting of distant expanses of water. Calm, interrupted
by ripple.

Sec. 17. And ripple, crossed by sunshine.

Of extended surfaces of water, as rendered by Turner, the Loch Katrine
and Derwent-water, of the Illustrations to Scott, and the Loch Lomond,
vignette in Rogers's Poems, are characteristic instances. The first of
these gives us the most distant part of the lake entirely under the
influence of a light breeze, and therefore entirely without reflections
of the objects on its borders; but the whole near half is untouched by
the wind, and on that is cast the image of the upper part of Ben-Venue
and of the islands. The second gives us the surface, with just so much
motion upon it as to prolong, but not to destroy, the reflections of the
dark woods,--reflections only interrupted by the ripple of the boat's
wake. And the third gives us an example of the whole surface so much
affected by ripple as to bring into exercise all those laws which we
have seen so grossly violated by Canaletto. We see in the nearest boat
that though the lines of the gunwale are much blacker and more
conspicuous than that of the cutwater, yet the gunwale lines, being
nearly horizontal, have no reflection whatsoever; while the line of the
cutwater, being vertical, has a distinct reflection of three times its
own length. But even these tremulous reflections are only visible as far
as the islands; beyond them, as the lake retires into distance, we find
it receives only the reflection of the gray light from the clouds, and
runs in one flat white field up between the hills; and besides all this,
we have another phenomenon, quite new, given to us,--the brilliant gleam
of light along the centre of the lake. This is not caused by ripple,
for it is cast on a surface rippled all over; but it is what we could
not have without ripple,--the light of a passage of sunshine. I have
already (Chap. I., Sec. 9) explained the cause of this phenomenon, which
never can by any possibility take place on calm water, being the
multitudinous reflection of the sun from the sides of the ripples,
causing an appearance of local light and shadow; and being dependent,
like real light and shadow, on the passage of the clouds, th