But in the Cathedral of Paris, though the same general incongruity exists in both choir and nave, there is a marked difference in the forms, the arrangements, and the adjustments of the respective vaulting systems. In the choir, the original design of 1163, [1] the vaulting shafts rise without break from the capitals of the ground-story to the springing of the vaults, varying in magnitude according to their respective loads. They are built up in courses—the central one being engaged against a projecting pilaster, and the lateral ones against the face of the pier. In the main group—that which carries the main transverse rib and two diagonals—the capitals are all on the same level. The central capital is set even with the wall, while the lateral ones are set diagonally, in the direction of the diagonal ribs. [2] These lateral capitals carry, besides the diagonal ribs, each a small shaft which rises to support the longitudinal rib whose springing is at a higher level—an arrangement of great significance as we shall presently see. In the intermediate group the arrangement is different. Here the central shaft only has its capital at the level of the springing of the great ribs, the side shafts rising unbroken to the higher points of springing of the longitudinal ribs, where they receive their capitals.
Figure 22 will illustrate these features. In this figure A exhibits the plan of the group of abaci of the capitals of the main vaulting shafts, and the sections of the ribs which they support; B is the plan of the abacus of the intermediate capital, with the section of the intermediate rib, and the sections of the side shafts; C is a perspective view of the main group, and D a perspective view of the intermediate
- ↑ Notre-Dame et ses premiers architectes, etc Par M. C. Bauchal. Paris, 1882.
- ↑ This is the usual arrangement of the vaulting capitals so long as the ribs retain a square section; but it shows the logic of the Gothic system to find that when the rib section is reduced to more or less of a wedge-shape—as it is in simple form at St. Denis, Senlis, and some other early buildings, and in more complex form at Amiens and elsewhere—then the central capital is, except in the earliest buildings, set diagonally, and the lateral ones are set even.
aisles—those so reinforced being opposite the great piers which carry the main transverse ribs and the diagonals of the vaults. This is hardly a justification of the construction as it exists. For this mode of reinforcement does not accommodate itself to the extra weight as well as thrust that falls on the main piers. And it is a mode that does not appeal to the eye at all. Moreover, it exists in the nave only. The dividing piers of the choir aisles are all alike.
