restored after having been elongated in the form of a rectangle (Fig. 74). Westward of this transept the choir is prolonged to the extent of four bays, and is terminated by a second transept—a construction which, with exception of a portion of its eastern side, is a work of the first quarter of the thirteenth century.
FIG. 74.
Lincoln Cathedral is vaulted throughout. The vaults of the choir are curious and even awkward in form; they are difficult to describe clearly in words, but the plan, Fig. 75, shows the arrangement of their ribs; and the elevation, B, Fig. 75, gives the form of the longitudinal arch which is also curious. It will be noticed that the lateral cells are set obliquely, so that they do not meet each other in the centre of the compartment. But in principle they are substantially the same as ordinary quadripartite vaults, each compartment being complete in itself. The rib system includes a longitudinal ridge rib, probably the first instance of the introduction of this structurally useless member which subsequently became an almost constant feature of English vaults. The longitudinal arch is not provided with a rib; but in place of it there is merely a slender moulding. This longitudinal arch springs from the same level as the transverse and diagonal arches, and hence the vaulting conoid is spread out over a considerable extent of wall (its
