St. Faith’s Chapel, Westminster Abbey. View looking west.
placed side by side, one apparently the square, and the other of the narrowest proportions; and in the outer vestibule beautiful miniature vaulting, on minute columns, and with the segmental arch; while in St. Faith’s Chapel, hard by, we have an excellent example of the sexpartite vault (Figs. [379], [380]). Parts of the aisles, too, are remarkable for the subdivision of their bays by transverse arches of the double orders of mouldings, giving a great nobleness and strength to their effect; and all these varieties are carried out with admirable detail and studied art.
It would lead me into too great length if I were to go into the moulding of the ribs, their combinations where grouping and intersecting one another in the springers, and the mode in which the shafts are arranged for their support. My illustrations will, however, do much to explain this. I must not omit to mention that in French buildings, and frequently in the earlier English specimens, the plans of the abaci of these shafts assume both forms and positions indicating the general section and the directions of the ribs they carry,[59] and that this is even shared by the bases; showing that the vaulting was the very first thing thought of and designed; and that, from the very floor of the building, it influenced the general design. This was lost in England by the introduction of the circular abacus.
I have hitherto dwelt wholly upon vaulting which has none but what I have termed functional ribs; that is to say, such as have a specific utility, as transverse ribs to mark the boundaries of the bays, and to strengthen the vault in its main span; diagonal ribs to fortify the angles of intersection; and wall-ribs to support the vaulting surfaces at their junction with the walls; and occasionally ridge ribs, though these more properly belong to the succeeding stage. The next stage in the history of vaulting is that in which other than merely functional ribs are made use of—intermediate ribs, in fact, to subdivide the spaces between those used during the previous period.
Fig. 381.
Fig. 382.
In square vaulting, one such additional rib is more usually introduced in each space ([Fig. 381]). In very oblong vaults two, and even three, were often introduced in the side spaces, though only one in the middle spaces ([Fig. 382]). It is clear that this addition necessitates the use of ridge ribs, as, without them, the point at which the intermediate ribs meet at their apex would want abutment. So reasonable, indeed, was this motive, that we often find the ridge rib to have been omitted between the intermediate ribs and the wall ribs, because there its use ceases.