Page:Charles Moore--Development and Character of Gothic Architecture.djvu/67

Rh vaulting, are now, having been shortened and slightly modified for the purpose, fairly well suited to such vaults as they carry. The two sides of the pilaster and the engaged shaft of the main pier carry respectively the main transverse rib and the two diagonals, while the intermediate shaft carries the intermediate transverse rib; and, there being no wall ribs, no other supports are required.

The principle of the sexpartite vault, with an appropriate vaulting system, thus, it would appear, accidentally developed and rudely embodied, in the Abbaye-aux-Hommes, became fruitful immediately in the Ile-de-France; where all chance work and groping experiment were being rapidly superseded by constructive foresight and consistency. Here in the Cathedral of Senlis there was nothing fortuitous or incongruous. The vaults and vaulting system were simultaneously conceived, and were, in all respects, parts of one whole. This is fully indicated by the piers, though not a stone of the primitive vaults remains in place. As the rib skeleton now determined the forms of the vaults, so with equal strictness did it determine the forms of the piers. These piers of Senlis are alternately massive and slender; the main pier being in section (Fig. 17) primarily a square intersected unsymmetrically by a rectangle. Against the four projecting faces of this pier rise, respectively, four engaged columns, a, b, c, and d, as shown in the section. Of these a supports the main transverse rib of the high vault, b and c support the archivolts of the ground-story, and d supports the transverse rib of the aisle vault. On each of the angles of the square central mass are worked round shafts, f, g, i, and j: f and g to carry the diagonal ribs of the high vault, and i and j to carry the diagonal ribs of the aisle vaults. While in the re-ntering angles on the choir side are placed the shafts e and h, which carry the longitudinal ribs. The only capitals on the ground-story level are those of the archivolt columns and the aisle vaulting shafts. The five members