The element of mass requires less comment. It appears in greatest number in those pictures which have little action, i.e. portraits and landscapes, and which are not yet symmetrical,-- in which last case mass is, of course, already balanced. In fact, it must of necessity exert a certain influence in every unsymmetrical picture, and so its percentage, even for genre pictures, is large. Thus we may regard the elements as both attracting attention to a certain spot and dispersing it over a field. Those types which are of a static character (landscapes, altar-pieces) abound in elements which disperse the attention; those which are of a dynamic character (genre picture), in those which make it stable. The ideal composition seems to combine the dynamic and static elements,--to animate, in short, the whole field of view, but in a generally bilateral fashion. The elements, in substitutional symmetry, are then simply means of introducing variety and action. As a dance in which there are complicated steps gives the actor and beholder a varied and thus vivified "balance," and is thus more beautiful than the simple walk, so a picture composed in substitutional symmetry is more rich in its suggestions of motor impulse, and thus more beautiful, than an example of geometrical symmetry. III The particular functions of the elements which are substituted for geometrical symmetry have been made clear; their presence lends variety and richness to the balance of motor impulses. But this quality of repose, or unity, given by balance, is also enriched by a unity for intuition,--a large outline in which all the elements are held together. Now this way of holding together varies; and I believe that it bears a very close relation to the subject and purpose of the picture. Examples of these types of composition may best be found by analyzing a few well-known pictures. We may begin with the class first studied, the Altar-piece, choosing a picture by Botticelli, in the Florence Academy. Under an arch is draped a canopy held up by angels; under this, again, sits the Madonna with the Child on her lap, on a throne, at the foot of which, on each side, stand three saints. The outline of the whole is markedly pyramidal; in fact, there are, broadly speaking, three pyramids, --of the arch, the canopy, and the grouping. A second, much less symmetrical example of this type, is given by another Botticelli in the Academy,--"Spring." Here the central female figure, topped by the floating Cupid, is slightly raised above the others, which, however, bend slightly inward, so that a triangle, or pyramid with very obtuse angle at the apex, is suggested; and the whole, which at first glance seems a little scattered, is at once felt, when this is grasped, as closely bound together.