function. The employment of such ribs appears to have had a singular fascination for the English builders at this epoch,—a fascination which gathered strength as the native taste asserted itself more and more, until, in the perpendicular style,—the first style of architecture that can properly be called English, it became predominant!
In these vaults of the nave of Lincoln there are six such ribs in each vaulting compartment—namely, four tiercerons, a in the plan, Fig. 79, and two liernes, b in the same figure. The longitudinal arches are round, and spring from a level not much above that of the springing of the transverse and diagonal ribs, in consequence of which the section of the vaulting conoid,
FIG. 79.
at the level a, in A, Fig. 80, is nearly square, as shown at B in the same figure. And hence here again the vault thrusts are not gathered upon the pier in a strictly Gothic manner. It will be also seen in the section B, Fig. 80, that the ribs of these vaults are so arranged as to give a convex curve to a portion of the vaulting conoid. This peculiarity marks an early step in the direction of the so-called fan vaulting system which subsequently became so conspicuous a feature of English pointed design. The rib system is mainly supported by the wall, which it penetrates, rather than by the vaulting shafts. These vaulting shafts consist of three very slender and closely grouped members rising from corbels placed just above the capitals of the lower piers; they are thus, like the vaulting shafts of Byland and Whitby, more decorative than structurally
