the apex and the slaves the base and side
lines. The other lines were arranged in part to draw away from this
apparent and very common form of composition. One has but to look through
a list of notable pictures to find evidence of the very frequent use of
these concentric lines drawing the vision from the lower corners of the
picture to an apex of the pyramid.

Now, herein lies the analogy between the simplest form of landscape
construction and the foreground or figure subject. The framework of both
is the pyramid, or what is termed _the structure of physical stability._
In the landscape the pyramid lies on its side, the apex receding. It is
the custom of some figure painters to construct entirely in pyramids, the
smaller items of the picture resolving themselves into minor pyramids. In
the single figure picture--the portrait, standing or sitting--the pyramidal
form annihilates the spaces on either side of the figure, which,
paralleling both the sides and the frame, would leave long quadrilaterals
in place of diminishing segments.

Whether the pyramid is in perspective or one described on the foreplane of
a picture, the principle is, _leading lines should carry the eye into the
picture or toward the subject,_ a point touched upon in the preceding
chapter.

When reverie begins in a picture, one's vision involuntarily makes a
circuit of the items presented, starting at the most interesting and
widening in its review toward the circumference, as ring follows ring when
a stone is thrown into water. The items of a picture may arrange
themselves in elliptical form, and the circuit may bend back into the
picture; or the form may be described on a vertical plane, but the circuit
should be there, and if two circuits may be formed the reverie will
continue that much longer. The outer circuit finished, the vision may
return to the centre again. If in a landscape, for instance, the interest
of the sky dominates that of the land, the vision will centre there and
come out through the foreground, and it is important that the eye have
such a course marked out for it, lest, left to itself, it slip away
through the sides, and the continuous chain of reverie be broken.

It is interesting to note in what cycles this great wheel of circular
observation revolves, directing the slow revolution of our gaze.

In one picture it takes us from the corner of the canvas to the extreme
distance and thence in a circuit back; in another it m