th your shaded squares,
and chiefly with these, the outline exercises being taken up only for
rest.

[Illustration: FIG. 2.]

As soon as you find you have some command of the pen as a shading
instrument, and can lay a pale or dark tint as you choose, try to
produce gradated spaces like Fig. 2, the dark tint passing gradually
into the lighter ones. Nearly all expression of form, in drawing,
depends on your power of gradating delicately; and the gradation is
always most skillful which passes from one tint into another very little
paler. Draw, therefore, two parallel lines for limits to your work, as
in Fig. 2, and try to gradate the shade evenly from white to black,
passing over the greatest possible distance, yet so that every part of
the band may have visible change in it. The perception of gradation is
very deficient in all beginners (not to say, in many artists), and you
will probably, for some time, think your gradation skillful enough, when
it is quite patchy and imperfect. By getting a piece of gray shaded
ribbon, and comparing it with your drawing, you may arrive, in early
stages of your work, at a wholesome dissatisfaction with it. Widen your
band little by little as you get more skillful, so as to give the
gradation more lateral space, and accustom yourself at the same time to
look for gradated spaces in Nature. The sky is the largest and the most
beautiful; watch it at twilight, after the sun is down, and try to
consider each pane of glass in the window you look through as a piece of
paper colored blue, or gray, or purple, as it happens to be, and observe
how quietly and continuously the gradation extends over the space in the
window, of one or two feet square. Observe the shades on the outside and
inside of a common white cup or bowl, which make it look round and
hollow;[4] and then on folds of white drapery; and thus gradually you
will be led to observe the more subtle transitions of the light as it
increases or declines on flat surfaces. At last, when your eye gets keen
and true, you will see gradation on everything in Nature.

14. But it will not be in your power yet awhile to draw from any objects
in which the gradations are varied and complicated; nor will it be a bad
omen for your future progress, and for the use that art is to be made of
by you, if the first thing at which you aim should be a little bit of
sky. So take any narrow space of evening sky, that you can usually see,
between the boughs of a