ness to interfere with his perception of the _art_ of the
building, and substitutes rude fractures and blotting stains for all its
fine chiselling and determined color, he has lost the end of his own
art.

Sec. 27. Effects of light, how necessary to the understanding of detail.

So far of aging; next of effects of light and color. It is, I believe,
hardly enough observed among architects that the same decorations are of
totally different effect according to their position and the time of
day. A moulding which is of value on a building facing south, where it
takes deep shadows from steep sun, may be utterly ineffective if placed
west or east; and a moulding which is chaste and intelligible in shade
on a north side, may be grotesque, vulgar, or confused when it takes
black shadows on the south. Farther, there is a time of day in which
every architectural decoration is seen to best advantage, and certain
times in which its peculiar force and character are best explained; of
these niceties the architect takes little cognizance, as he must in some
sort calculate on the effect of ornament at all times; but to the artist
they are of infinite importance, and especially for this reason, that
there is always much detail on buildings which cannot be drawn as such,
which is too far off, or too minute, and which must consequently be set
down in short-hand of some kind or another; and, as it were, an
abstract, more or less philosophical, made of its general heads. Of the
style of this abstract, of the lightness, confusion, and mystery
necessary in it, I have spoken elsewhere; at present I insist only on
the arrangement and matter of it. All good ornament and all good
architecture are capable of being put into short-hand; that is, each has
a perfect system of parts, principal and subordinate, of which, even
when the complemental details vanish in distance, the system and anatomy
yet remain visible so long as anything is visible; so that the divisions
of a beautiful spire shall be known as beautiful even till their last
line vanishes in blue mist, and the effect of a well-designed moulding
shall be visibly disciplined, harmonious, and inventive, as long as it
is seen to be a moulding at all. Now the power of the artist of marking
this character depends not on his complete knowledge of the design, but
on his experimental knowledge of its salient and bearing parts, and of
the effects of light and shadow, by which their saliency is best