masses, and when near the centre, as being at the same time the
"heaviest" part of the picture, it serves as a fulcrum or centre
to bind the parts--always harder to bring together than in the
other types of pictures--into a close unity. The most frequent
form of this arrangement is a diagonal, which just saves itself
by turning up at its far end. Thus the mass, and hence usually
the special interest of the picture, is on the one side, on
the other the vista and the sloping line of the diagonal. In
very few cases is the vista behind an attractive or noticeable
part of the picture, the fact showing that it acts in opposition
to the latter, leading the eye away from it, and thus serving at
once the variety and richness of the picture, and its unity. A
complete diagonal would have line and vista both working at the
extreme outer edge of the picture, and thus too strongly,--
unless, indeed, balanced by very striking elements near the
outer edge.

This function of the vista as a unifying element is of interest
in connection with the theory of Hildebrand,<1> that the landscape
should have a narrow foreground and wide background, since that
is most in conformity with our experience. He adduces Titian's
"Sacred and Profane Love" as an example. But of the general
principle it may be said that not the reproduction of nature,
but the production of beauty, is the aim of composition, and that
this aim is best reached by focusing the eye by a narrow background,
i.e. vista. No matter how much it wanders, it returns to that
central spot and is held there, keeping hold on all the other
elements. Of Hildebrand's example it may be said that the
pyramidal composition, with the dark and tall tree in the centre,
effectually accomplishes the binding together of the two figures,