got in good water-color drawing by these two expedients,
interlacing the colors, or retouching the lower one with fine darker
drawing in an upper. Sponging and washing for dark atmospheric effect is
barbarous, and mere tyro's work, though it is often useful for passages
of delicate atmospheric light.

175. (_c._) When you have time, practice the production of mixed tints
by interlaced touches of the pure colors out of which they are formed,
and use the process at the parts of your sketches where you wish to get
rich and luscious effects. Study the works of William Hunt, of the Old
Water-color Society, in this respect, continually, and make frequent
memoranda of the variegations in flowers; not painting the flower
completely, but laying the ground color of one petal, and painting the
spots on it with studious precision: a series of single petals of
lilies, geraniums, tulips, etc., numbered with proper reference to their
position in the flower, will be interesting to you on many grounds
besides those of art. Be careful to get the gradated distribution of the
spots well followed in the calceolarias, foxgloves, and the like; and
work out the odd, indefinite hues of the spots themselves with minute
grains of pure interlaced color, otherwise you will never get their
richness or bloom. You will be surprised to find as you do this, first,
the universality of the law of gradation we have so much insisted upon;
secondly, that Nature is just as economical of _her_ fine colors as I
have told you to be of yours. You would think, by the way she paints,
that her colors cost her something enormous; she will only give you a
single pure touch, just where the petal turns into light; but down in
the bell all is subdued, and under the petal all is subdued, even in the
showiest flower. What you thought was bright blue is, when you look
close, only dusty gray, or green, or purple, or every color in the world
at once, only a single gleam or streak of pure blue in the center of it.
And so with all her colors. Sometimes I have really thought her
miserliness intolerable: in a gentian, for instance, the way she
economizes her ultramarine down in the bell is a little too bad.[49]

176. Next, respecting general tone. I said, just now, that, for the sake
of students, my tax should not be laid on black or on white pigments;
but if you mean to be a colorist, you must lay a tax on them yourself
when you begin to use true color; that is to say, you must