so that a vista is not needed. A wide background without that
tree would leave them rather disjointed.

<1> Op cit., p. 55.

In general, it may be said that balance in landscape is effected
between mass and interest on one side and vista and line on the
other; and that union is given especially by the use of vista.


II

The experimental treatment of the isolated elements detected
the particular function of each in distributing attention in
the field of view. But while all are possibly operative in a
given picture, some are given, as we have seen, much more
importance than others, and in pictures of different types
different elements predominate. In those classes with a
general symmetrical framework, such as the altar and Madonna
pieces, the elements of interest and direction of attention
determine the balance, for they appear as variations in a
symmetry which has already, so to speak, disposed of mass and
line. They give what action there is, and where they are very
strongly operative, they are opposed by salient lines and deep
vistas, which act more strongly on the attention than does mass.
Interest keeps its predominance throughout the types, except in
the portraits, where the head is usually in the central line.
But even among the portraits it has a respectable representation,
as jewels, embroideries, beautiful hands, etc., count largely
too in composition.