be more reposeful than the latter. It may aid the solution of
the problem to remember that the composition taken as a whole
has to meet the demand for unity, at the same time that it
allows free play to the natural expression of the subject. The
altar-piece has to bring about a concentration of attention to
express or induce a feeling of reverence. This is evidently
accomplished by the suggestion of the converging lines to the
fixation of the high point in the picture,--the small area
occupied by the Madonna and Child,--and by the subordination
of the free play of other elements. The contrast between the
broad base and the apex gives a feeling of solidity, of repose;
and it seems not unreasonable to suppose that the tendency to
rest the eyes above the centre of the picture directly induces
the associated mood of reverence or worship. Thus the
pyramidal form serves two ends; primarily that of giving unity,
and secondarily, by the peculiarity of its shape, that of
inducing the feeling-tone appropriate to the subject of the
picture.

Applying this principle to the so-called "active" pictures, we
see that the natural movement of attention between the different
"actors" in the picture must be allowed for, while yet unity is
secured. And it is clear that the diagonal type is just fitted
for this. The attention sweeps down from the high side to the
low, from which it returns through some backward suggestion of
lines or interest in the objects of the high side. Action and
reaction--movement and return of attention--is inevitable under
the conditions of this type; and this it is which allows the
free play,--which, indeed, CONSTITUTES and expresses the activity
belonging to the subject, just as the fixation of the pyramid