comes within the field of vision, and the whole impression can be
readily grasped without the main lines being, as it were, underlined.
But in a big picture one of the greatest difficulties is to get it to
read simply, to strike the eye as one impression. Its size making it
difficult for it to be got comfortably within the field of vision, every
artifice has to be used to give it "breadth of treatment," as it is
called, and nothing interferes with this like detail.

XIII

VARIETY OF MASS

The masses that go to make up a picture have variety in their #shape#,
their #tone values#, their #edges#, in #texture# _or_ #quality#, and in
#gradation#. Quite a formidable list, but each of these particulars has
some rhythmic quality of its own about which it will be necessary to say
a word.

[Sidenote: Variety of Shape.]

As to variety of shape, many things that were said about lines apply
equally to the spaces enclosed by them. It is impossible to write of the
rhythmic possibilities that the infinite variety of shapes possessed by
natural objects contain, except to point out how necessary the study of
nature is for this. Variety of shape is one of the most difficult things
to invent, and one of the commonest things in nature. However
imaginative your conception, and no matter how far you may carry your
design, working from imagination, there will come a time when studies
from nature will be necessary if your work is to have the variety that
will give life and interest. Try and draw from imagination a row of elm
trees of about the same height and distance apart, and get the variety
of nature into them; and you will see how difficult it is to invent. On
examining your work you will probably discover two or three pet forms
repeated, or there may be only one. Or try and draw some cumulus clouds
from imagination, several groups of them across a sky, and you will
find how often again you have repeated unconsciously the same forms. How
tired one gets of the pet cloud or tree of a painter who does not often
consult nature in his pictures. Nature is the great storehouse of
variety; even a piece of coal will suggest more interesting rock-forms
than you can invent. And it is fascinating to watch the infinite variety
of graceful forms assumed by the curling smoke from a cigarette, full of
suggestions for beautiful line arrangements. If this variety of form in
your work is allowed to become excessive it will overpower the unity