X. This, however, may perhaps be partly attributable to some accommodation of the accidental distortions which evidently took place in the walls of the cathedral during their building, as much as in those of the campanile. To my mind, those of the Duomo are far the most wonderful of the two: I do not believe that a single pillar of its walls is absolutely vertical: the pavement rises and falls to different heights, or rather the plinth of the walls sinks into it continually to different depths, the whole west front literally overhangs (I have not plumbed it; but the inclination may be seen by the eye, by bringing it into visual contact with the upright pilasters of the Campo Santo): and a most extraordinary distortion in the masonry of the southern wall shows that this inclination had begun when the first story was built. The cornice above the first arcade of that wall touches the tops of eleven out of its fifteen arches; but it suddenly leaves the tops of the four westernmost; the arches nodding westward and sinking into the ground, while the cornice rises (or seems to rise), leaving at any rate, whether by the rise of the one or the fall of the other, an interval of more than two feet between it and the top of the western arch, filled by added courses of masonry. There is another very curious evidence of this struggle of the architect with his yielding wall in the columns of the main entrance. (These notices are perhaps somewhat irrelevant to our immediate subject, but they appear to me highly interesting; and they, at all events, prove one of the points on which I would insist,--how much of imperfection and variety in things professing to be symmetrical the eyes of those eager builders could endure: they looked to loveliness in detail, to nobility in the whole, never to petty measurements.) Those columns of the principal entrance are among the loveliest in Italy; cylindrical, and decorated with a rich arabesque of sculptured foliage, which at the base extends nearly all round them, up to the black pilaster in which they are lightly engaged: but the shield of foliage, bounded by a severe line, narrows to their tops, where it covers their frontal segment only; thus giving, when laterally seen, a terminal line sloping boldly outwards, which, as I think, was meant to conceal the accidental leaning of the western walls, and, by its exaggerated inclination in the same direction, to throw them by comparison into a seeming vertical.