n without
rivets. It is of course desirable that this thin sub-arch of marble
should project enough to sustain the facing of the wall; and the reader
will see, in Fig. LVII., that its edge forms a kind of narrow band round
the arch (_b_), a band which the least enrichment would render a
valuable decorative feature. Now this band is, of course, if the
soffit-pieces project a little beyond the face of the wall-pieces, a
mere fillet, like the wooden gunwale in Plate IX.; and the question is,
how to enrich it most wisely. It might easily have been dogtoothed, but
the Byzantine architects had not invented the dogtooth, and would not
have used it here, if they had; for the dogtooth cannot be employed
alone, especially on so principal an angle as this of the main arches,
without giving to the whole building a peculiar look, which I can not
otherwise describe than as being to the eye, exactly what untempered
acid is to the tongue. The mere dogtooth is an _acid_ moulding, and can
only be used in certain mingling with others, to give them piquancy;
never alone. What, then, will be the next easiest method of giving
interest to the fillet?

[Illustration: Fig. LVIII.]

Sec. XIII. Simply to make the incisions square instead of sharp, and to
leave equal intervals of the square edge between them. Fig. LVIII. is
one of the curved pieces of arch armor, with its edge thus treated; one
side only being done at the bottom, to show the simplicity and ease of
the work. This ornament gives force and interest to the edge of the
arch, without in the least diminishing its quietness. Nothing was ever,
nor could be ever invented, fitter for its purpose, or more easily cut.
From the arch it therefore found its way into every position where the
edge of a piece of stone projected, and became, from its constancy of
occurrence in the latest Gothic as well as the earliest Byzantine, most
truly deserving of the name of the "Venetian Dentil." Its complete
intention is now, however, only to be seen in the pictures of Gentile
Bellini and Vittor Carpaccio; for, like most of the rest of the
mouldings of Venetian buildings, it was always either gilded or
painted--often both, gold being laid on the faces of the dentils, and
their recesses colored alternately red and blue.

Sec. XIV. Observe, however, that the reason above given for the
_universality_ of this ornament was by no means the reason of its
_invention_. The Venetian dentil is a particular applicatio