each is, in a manner and to a degree not possible with any of
the other arts, convertible into the other, by reason of the
correspondence subsisting between intervals of time and intervals of
space. A perception of this may have inspired the famous saying
that architecture is _frozen music_, a poetical statement of a
philosophical truth, since that which in music is expressed by means
of harmonious intervals of time and pitch, successively, after the
manner of time, may be translated into corresponding intervals of
architectural void and solid, height and width.

In another sense music and architecture are allied. They alone of
all the arts are purely creative, since in them is presented, not
a likeness of some known idea, but _a thing-in-itself_ brought to
a distinct and complete expression of its nature. Neither a musical
composition nor a work of architecture depends for its effectiveness
upon resemblances to natural sounds in the one case, or to natural
forms in the other. Of none of the other arts is this to such a degree
true: they are not so much creative as re-creative, for in them all
the artist takes his subject ready made from nature and presents it
anew according to the dictates of his genius.

The characteristic differences between music and architecture are the
same as those which subsist between time and space. Now time and space
are such abstract ideas that they can be dealt with best through
their corresponding correlatives in the natural world, for it is a
fundamental theosophic tenet that nature everywhere abounds in such
correspondences; that nature, in its myriad forms, is indeed the
concrete presentment of abstract unities. The energy which everywhere
animates form is a type of time within space; the mind working in
and through the body is another expression of the same thing.