some constructive necessity affords an obvious and higher reason for it.
Then, again, we find the unwritten law running throughout all
architecture that a progress of line in one direction requires to be
stopped in a marked and distinct manner when it has run its course, and
we find a similarly felt necessity in regard to musical form. The
repetition so common at the close of a piece of music of the same chord
several times in succession is exactly analogous to the repetition of
cross lines at the necking of a Doric column to stop the vertical lines
of the fluting, or to the strongly marked horizontal lines of a cornice
which form the termination of the height or upward progress of an
architectural design. The analogy is here very close. A less close
analogy may also be felt between an architectural and a musical
composition regarded as a whole. A fugue of Bach's is really a built-up
structure of tones (as Browning has so finely put it in his poem, "Abt
Vogler"), in accordance with certain ideas of relation and proportion,
just as a temple or a cathedral is a built-up structure of lines and
spaces in accordance with ideas of relation and proportion. Both appeal
to the same sense of proportion and construction in the brain; the one
through the ear, the other through the eye. Then, in regard to
architecture again, we have further limiting conditions arising not only
out of the principle of construction employed, but out of the physical
properties of the very material we employ. A treatment that is suitable
and expressive for a stone construction is quite unsuitable for a timber
construction. Details which are effective and permanent in marble are
ineffective and perishable in stone, and so; on and the outcome of all
this is that all architectural design has to be judged, not by any easy
and ready reference to exterior physical nature, with which it has
nothing to do, but by a process of logical reasoning as to the relation
of the design to the practical conditions, first, which are its basis,
and as to the relation of the parts to each other. Of course beyond all