ec. XIX.

CHAPTER XXVIII.

THE ARCHIVOLT AND APERTURE.

[Illustration: Plate XIX.
ARCHIVOLT DECORATION.
AT VERONA.]

Sec. I. If the windows and doors of some of our best northern Gothic
buildings were built up, and the ornament of their archivolts concealed,
there would often remain little but masses of dead wall and unsightly
buttress; the whole vitality of the building consisting in the graceful
proportions or rich mouldings of its apertures. It is not so in the
south, where, frequently, the aperture is a mere dark spot on the
variegated wall; but there the column, with its horizontal or curved
architrave, assumes an importance of another kind, equally dependent
upon the methods of lintel and archivolt decoration. These, though in
their richness of minor variety they defy all exemplification, may be
very broadly generalized.

Of the mere lintel, indeed, there is no specific decoration, nor can be;
it has no organism to direct its ornament, and therefore may receive any
kind and degree of ornament, according to its position. In a Greek
temple, it has meagre horizontal lines; in a Romanesque church, it
becomes a row of upright niches, with an apostle in each; and may become
anything else at the architect's will. But the arch head has a natural
organism, which separates its ornament into distinct families, broadly
definable.

Sec. II. In speaking of the arch-line and arch masonry, we considered
the arch to be cut straight through the wall; so that, if half built, it
would have the appearance at _a_, Fig. LXIX. But in the chapter on Form
of Apertures, we found that the side of the arch, or jamb of the
aperture, might often require to be bevelled, so as to give the section
_b_, Fig. LXIX. It is easily conceivable that when two ranges of
voussoirs were used, one over another, it would be easier to leave
those beneath, of a smaller diameter, than to bevel them to accurate
junction with those outside. Whether influenced by this facility, or by
decorative instinct, the early northern builders often substitute for
the bevel the third condition, _c_, of Fig. LXIX.; so that, of the three
forms in that figure, _a_ belongs principally to the south, _c_ to the
north, and _b_ indifferently to both.

[Illustration: Fig. LXIX.]

Sec. III. If the arch in the northern building be very deep, its depth
will probably be attained by a succession of steps, like that in _c_; and
the richest r