III. MURANO 47

and the broadest sides of the main piers are 4 feet 7 inches wide, their narrowest sides 3 feet 6 inches. The distance a c from the outmost angle of these piers to the beginning of the curve of the apse is 25 feet, and from that point the apse is nearly semicircular, but it is so encumbered with Renaissance fittings that its from cannot be ascertained with perfect accuracy. It is roofed by a concha, or semi-dome; and the external arrangement of its walls provides for the security of this dome by what is, in fact, a system of buttresses as effective and definite as that of any of the Northern churches, although the buttresses are obtained entirely by adaptations of the Roman shaft and arch, the lower story being formed by a thick mass of wall lightened by ordinary semicircular round-headed niches, like those used so extensively afterwards in Renaissance architecture, each niche flanked by a pair of shafts standing clear of the wall, and bearing deeply moulded arches thrown over the niche. The wall with its pillars thus forms a series of massy buttresses (as seen in the ground plan), on the top of which is an open gallery, backed by a thinner wall, and roofed by arches whose shafts are set above the pairs of shafts below. On the heads of these arches rests the roof. We have, therefore, externally a heptagonal apse, chiefly of rough and common brick, only with marble shafts and a few marble ornaments; but for that very reason all the more interesting, because it shows us what may be done, and was done, with materials such as are now at our own command; and because in its proportions, and in the use of the few ornaments it possesses, it displays a delicacy of feeling rendered doubly notable by the roughness of the work in which laws so subtle are observed, and with which so thoughtful ornamentation is associated.

§ 15. First, for its proportions: I shall have occasion in Chapter V. to dwell at some length on the peculiar subtlety of the early Venetian perception for ratios of magnitude;¹ the relations of the sides of this heptagonal apse supply

¹ [See below, pp. 148-153.]

[Version 0.04: March 2008]