251. I have hardly said anything about waves of torrents or waterfalls,
as I do not consider them subjects for beginners to practice upon; but,
as many of our younger artists are almost breaking their hearts over
them, it may be well to state at once that it is physically impossible
to draw a running torrent quite rightly, the luster of its currents and
whiteness of its foam being dependent on intensities of light which art
has not at its command. This also is to be observed, that most young
painters make their defeat certain by attempting to draw running water,
which is a lustrous object in rapid motion, without ever trying their
strength on a lustrous object standing still. Let them break a coarse
green-glass bottle into a great many bits, and try to paint those, with
all their undulations and edges of fracture, as they lie still on the
table; if they cannot, of course they need not try the rushing crystal
and foaming fracture of the stream. If they can manage the glass bottle,
let them next buy a fragment or two of yellow fire-opal; it is quite a
common and cheap mineral, and presents, as closely as anything can, the
milky bloom and color of a torrent wave: and if they can conquer the
opal, they may at last have some chance with the stream, as far as the
stream is in any wise possible. But, as I have just said, the bright
parts of it are _not_ possible, and ought, as much as may be, to be
avoided in choosing subjects. A great deal more may, however, be done
than any artist has done yet, in painting the gradual disappearance and
lovely coloring of stones seen through clear and calm water.
Students living in towns may make great progress in rock-drawing by
frequently and faithfully drawing broken edges of common roofing slates,
of their real size.