quadripartite vault, which was now greatly improved in form, came into general, though not invariable,[1] use; and in connection with it the form of the lower pier, which had been developed in the west bay of Paris, was generally adopted.
The improvements in the vault consisted in replacing the round longitudinal arch—such as that of the choir of Noyon and of St. Germain des Prés—by a pointed arch (such as had been employed in the sexpartite vaults of Paris, and other ontemporaneous buildings); and in making the crowns of all the arches reach more nearly to the same level, thus doing away with the excessive doming that had characterised the earlier quadripartite vaults.
There is one most important characteristic of French-Gothic vaults that often passes unnoticed, the real significance of which has not, I believe, as yet been explained by those writers who have noticed it. It is that (alluded to above, page 39, in connection with the vaults of the Abbaye-aux-Hommes at Caen, and of Notre Dame at Paris) of the twisted surfaces caused by stilting the longitudinal arches, so that their springing begins at a much higher level than that of the main arches.
A frequent misunderstanding of the Gothic vault has arisen from supposing that, by taking advantage of the properties of the pointed arch, all its ribs were made to spring from the same level and reach the same height, however they might vary in span. [2] It is indeed true that the use of the pointed arch made this possible, but it is equally true that in strictly Gothic vaults the pointed arch was never so used; in such vaults the longitudinal rib was always stilted. This fact is noticed by Willis, [3] who merely remarks in relation to it that "it is a very universal arrangement of clerestory vaults, and is productive of great beauty and convenience, but it leads to some difficulty in the form and arrangement of the vaulting surface." Other writers have supposed that this arrangement was intended to provide for largeness of clerestory
- ↑ The sexpartite vaults of Bourges date from the latter part of the first half of the thirteenth century. Those of the choir of Beauvais are still later. But though thus sometimes still employed, the sexpartite form had now become as unusual as, nearly a century before, the quadripartite form had been.
- ↑ See, for instance, Ferguson's History of Architecture, vol. i. p. 517.
- ↑ In his essay on the Construction of the Vaults of the Middle Ages, published in the Transactions of the Royal Institute of British Architects for the Year 1842.
