of Polarity finds
fulfilment in the complex and flowing lines of the draped figures
contrasted with the simple parallelogram of the cloth-covered table,
and the severe architecture of the room. The law of Trinity is
exemplified in the three windows, and in the subdivision of the twelve
figures of the disciples into four groups of three figures each. The
law of Consonance appears in the repetition of the horizontal lines
of the table in the ceiling above; and in the central triangle before
referred to, continued and echoed, as it were, in the triangular
supports of the table visible underneath the cloth. The law of
Diversity in Monotony is illustrated in the varying disposition of the
heads of the figures in the four groups of three; the law of Balance
in the essential symmetry of the entire composition; the law of
Rhythmic Change in the diminishing of the wall and ceiling spaces; and
the law of Radiation in the convergence of all the perspective lines
to a single significant point.

To illustrate further the universality of these laws, consider now
their application to a single work of architecture: the Taj Mahal, one
of the most beautiful buildings of the world (Illustration 36). It is
a unit, but twofold, for it consists of a curved part and an angular
part, roughly figured as an inverted cup upon a cube; each of these
(seen in parallel perspective, at the end of the principal vista) is
threefold, for there are two sides and a central parallelogram, and
two lesser domes flank the great dome. The composition is rich in
consonances, for the side arches echo the central one, the subordinate
domes the great dome, and the lanterns of the outstanding minarets
repeat the principal motif. Diversity in Monotony appears abundantly
in the ornament, which is intricate and infinitely various; the law of
Balance is everywhere operative in the symmetry of the entire design.
Rhythmic Change appears in the tapering of the minarets, the outlines
of the domes and their mass relations to one another; and finally,
the whole effect is of radiation from a central point, of elements
disposed on radial lines.

It would be fatuous to contend that the prime object of a work of
architecture is to obey and illustrate these laws. The prime object of
a work of architecture is to fulfill certain definite conditions in a
practical, economical, and admirable way, and in fulfilling to express
as far as possible these conditions, making the form expre