The direction of attention is most operative among the portraits.
Since these pictures represent no action, it must be given by
those elements which move and distribute the attention; in
accordance with which principle we find line also unusually
influential. As remarked above, altar-pieces and Madonna pictures,
also largely without action, depend largely for it on the direction
of attention.

The vista, as said above, rivets and confines the attention. We
can, therefore, understand how it is that in the genre pictures it
appears very numerous. The active character of these pictures
naturally requires to be modified, and the vista introduces a
powerful balancing element, which is yet quiet; or, it might be
said, inasmuch as energy is certainly expended in plunging down
the third dimension, the vista introduces an element of action
of counterbalancing character. In the landscape it introduces
the principal element of variety. It is always to be found in
those parts of the picture which are opposed to other powerful
elements, and the "heavier" the other side, the deeper the vista.
Also in pictures with two groups it serves as a kind of fulcrum,
or unifying element, inasmuch as it rivets the attention between
the two detached sides.

The direction of suggestion by means of the indication of a line,
quite naturally is more frequent in the Madonna picture and
portrait classes. Both these types are of large simple outline,
so that line would be expected to tell. In a decided majority
of cases, combined with vista--the shape being more or less a
diagonal slope--it is clear that it acts as a kind of bond