Fig. 20.—Rose Window from the Transept of Lincoln Cathedral. (1342-1347.)
In perpendicular windows spaces of enormous size are occupied by the mullions and tracery. Horizontal bars, called transoms, are now for the first time introduced, and the upright bars or mullions form with them a kind of stone grating; but below each transom a series of small stone arches forms heads to the lights below that transom, and a minor mullion often springs from the head of each of these arches, so that as the window increases in height, the number of its lights increases. The character of the cusping changed again, the cusps becoming club-headed in their form (Fig. [21]).
Fig. 21.—Perpendicular Window.
Arches in the great arcades of churches, or in the smaller arcades of cloisters, or used as decorations to the surface of the walls, were made acute, obtuse, or segmental, to suit the duty they had to perform; but when there was nothing to dictate any special shape, the arch of the E. E. period was by preference acute[18] and of lofty proportions, and that of the Dec. less lofty, and its head equilateral (i.e. described so that if the ends of the base of an equilateral triangle touch the two points from which it springs, the apex of the angle shall touch the point of the arch). In the Perp. period the four centred depressed arch, sometimes called the Tudor arch, was introduced, and though it did not entirely supersede the equilateral arch, yet its employment became at last all but universal, and it is one of the especially characteristic features of the Tudor period.
Roofs and Vaults.
The external and the internal covering of a building are very often not the same; the outer covering is then usually called a roof—the other, a vault or ceiling. In not a few Gothic buildings, however, they were the same; such buildings had what are known as open roofs—i.e. roofs in which the whole of the timber framing of which they are constructed is open to view from the interior right up to the tiles or lead. Very few open roofs of E. E. character are now remaining, but a good many parish churches retain roofs of the Dec., and more of the Perp. period. The roof of Westminster Hall (Perp., erected 1397) shows how fine an architectural object such a roof may become. The roof of the hall of Eltham Palace (Fig. [22]) is another good example. Wooden ceilings, often very rich, are not uncommon, especially in the churches of Norfolk and Suffolk, but greater interest attaches to the stone vaults with which the majority of Gothic buildings were erected, than to any other description of covering to the interiors of buildings.
The vault was a feature rarely absent from important churches, and the structural requirements of the Gothic vault were among the most influential of the elements which determined both the plan and the section of a mediæval church. There was a regular growth in Gothic vaults. Those of the thirteenth century are comparatively simple; those of the fourteenth are much richer and more elaborate, and often involve very great structural difficulties. Those of the fifteenth are more systematic, and consequently more simple in principle than the ones which preceded them, but are such marvels of workmanship, and so enriched by an infinity of parts, that they astonish the beholder, and it appears, till the secret is known, impossible to imagine how they can be made to stand.