126 THE STONES OF VENICE CONSTRUCTION

group he should, if possible, avoid a marked separation between the large central shaft and its satellites; for if this exist, the satellites will either appear useless altogether, or else, which is worse, they will look as if they were meant to keep the central shaft together by wiring or caging it in; like iron rods set round a supple cylinder,-a fatal fault in the piers of Westminster Abbey, and, in a less degree, in the noble nave of the cathedral of Bourges.

§ 18. While, however, we have been thus subdividing or assembling our shafts, how far has it been possible to retain their curved or tapered outline? So long as they remain distinct and equal, however close to each other, the independent curvature may evidently be retained. But when once they come in contact it is equally evident that a column, formed of shafts touching at the base and separate at the top, would appear as if in the very act of splitting asunder. Hence, in all the closely arranged groups, and especially those with a central shaft, the tapering is sacrificed: and with less cause for regret, because it was a provision against subsidence or distortion, which cannot now take place with the separate members of the group. Evidently, the work, if safe at all, must be executed with far greater accuracy and stability when its supports are so delicately arranged, than would be implied by such precaution. In grouping shafts, therefore, a true perpendicular line is, in nearly all cases, given to the pier; and the reader will anticipate that the two schools, which we have already found to be distinguished, the one by its perpendicular and pierced shafts, and the other by its curved and block shafts, will be found divided also in their employment of grouped shafts;-it is likely that the idea of grouping, however suggested, will be fully entertained and acted upon by the one, but hesitatingly by the other; and that we shall find, on the one hand, buildings displaying sometimes massy piers of small stones, sometimes clustered piers of rich complexity, and on the other, more or less regular succession of block shafts, each treated as entirely independent of those around it.

[Version 0.04: March 2008]