abacus.

Sec. XLIV. The lowest capital in Plate XVIII. is from St. Mark's, and
singular in having double spurs; it is therefore to be compared with
the doubly spurred base, also from St Mark's, in Plate XI. In other
respects it is a good example of the union of breadth of mass with
subtlety of curvature, which characterises nearly all the spurred
capitals of the convex school. Its plan is given in Fig. LXVIII.: the
inner shaded circle is the head of the shaft; the white cross, the
bottom of the capital, which expands itself into the external shaded
portions at the top. Each spur, thus formed, is cut like a ship's bow,
with the Doric profile; the surfaces so obtained are then charged with
arborescent ornament.

Sec. XLV. I shall not here farther exemplify the conditions of the
treatment of the spur, because I am afraid of confusing the reader's
mind, and diminishing the distinctness of his conception of the
differences between the two great orders, which it has been my principal
object to develope throughout this chapter. If all my readers lived in
London, I could at once fix this difference in their minds by a simple,
yet somewhat curious illustration. In many parts of the west end of
London, as, for instance, at the corners of Belgrave Square, and the
north side of Grosvenor Square, the Corinthian capitals of newly-built
houses are put into cages of wire. The wire cage is the exact form of
the typical capital of the convex school; the Corinthian capital,
within, is a finished and highly decorated example of the concave. The
space between the cage and capital is the limit of ornamentation.

Sec. XLVI. Those of my readers, however, to whom this illustration is
inaccessible, must be content with the two profiles, 13 and 14, on Plate
XV. If they will glance along the line of sections from 1 to 6, they
will see that the profile 13 is their final development, with a
superadded cornice for its abacus. It is taken from a capital in a very
important ruin of a palace, near the Rialto of Venice, and hereafter to
be described; the projection, outside of its principal curve, is the
profile of its _superadded_ leaf ornamentation; it may be taken as one
of the simplest, yet a perfect type of the concave group.

Sec. XLVII. The profile 14 is that of the capital of the main shaft of
the northern portico of St. Mark's, the most finished example I ever met
with of the convex family, to which, in spite of the central inward bend
of it