But as aesthetic diversity rests upon a broader
unity, it appears in art as true contrast, in which
the diverse parts or elements are regarded as indeed
different, yet as tied together in a true unity, as
l)clonging to one whole. Architecture avails itself
of \his principle everywhere — in size, in form, in
light, in color. The magnitude of a structure, of its
area and of its height, can be shown only by con-
trast. We enter into an adequate conception of the
vastness of St. Peter's at Rome only as we measure
its immense reaches by some relatively small object,
as the angels supporting the lavers, or the bronze
statue of St. Peter, or some more integral part of
the building, as a chapel or a column* The
apparent greatness of a structure, indeed, dependii



^1»EC1AL LAWS. igt

in a large degree on the skillful contrasting of like
parts. The simplicity and uniformity of a Grecian
temple make it appear much smaller than a Byzan-
tian cathedral of the same size, with its manifold
domes of varying dimensions, or a Gothic church,
wiA its multiplied parts.
So the beauty of form and of outline may be
greatly enhanced by the variations from the recti-
linear to the curvilinear, by diversity of curves, by
combinations of the vertical with horizontal lines.
In like manner, a great part of the beauty in a
colonnade and in architectural sculpture and other
decoration depends on the skillful contrasts of light
and shade. The illimitable combinations of colors
have in all styles of architecture, by the tasteful
contrasting of hues, been turned to aesthetic
account. Polychromy, indeed, both exterior and
interior^ constitutes one leading department in the
art of architecture.
