only to suggest movement, but also to describe
its direction and force. It is, in fact, _the line of movement_. The
principle may be seen in a simpler way, as Hogarth points out in his
"Analysis of Beauty," by observing the line described along a wall by
the head of a man walking along the street. Or, as we may see sometimes
near the coast, trees exposed to the constant pressure of the wind
illustrate this recurrence of lines in the same direction governing
their general shape; and as each tree is forced to spread in the
direction away from the wind, the effect is that of their being always
struggling against its pressure even in the calmest weather; and this is
entirely due to our association of wind-movement with this peculiar
linear expression.

[Illustration (f011): Lines Expressive of Movement: Effect of Wind Upon
Trees]

Flowing water, again, is expressed by certain recurring wave-lines,
which remind us of the ancient linear symbols of the zigzag and meander
used from the earliest times to express water. In the streams that
channel the sands of the sea-shore when the tide recedes we may see
beautiful flowing lines, sometimes crossing like a network, and
sometimes running into a series of shell-like waves; while the sands
themselves are ribbed and channelled and modelled by the recurring
movement of the waves, which leave upon them the impress and the
expression of their motion (much as in a more delicate medium the
air-currents impress the fields of cloud, and give them their
characteristic forms).

[Illustration (f012): Line Arrangement in Ribbed Sea Sand]

[Linear Expression of Textures]

Textures and surfaces, too, fall within the range of linear expression.
One would naturally use lines of totally different consistency and
character to express rough or smooth surfaces: to express the difference
of value, for instance, between the ivory-like smoothness of an egg and
the scaly surface of a pine-cone, entirely different qualities of line
are obviously wanted. The firm-set yet soft feathers of the plumage of a
bird must be rendered by a very different touch from the shining scales
of a fish. The hair and horns of animals, delicate human features,
flowers, the sinuous lines of thin drapery, or the broad massive folds
of heavy robes, all demand from the designer and draughtsman in line
different kinds of suggestive expression, a translation or rendering of
natural fac