Page:Charles Moore--Development and Character of Gothic Architecture.djvu/110

Rh pointed arched opening above the level of the springing of the vaults, and although larger than such openings had been in Romanesque design, it nevertheless is simply an opening in a wall, the area of the solid still being greater than that of the void. Beneath the clerestory is a circular opening, filled with a peculiar and beautiful form of tracery, occupying the space between the vaults of the triforium gallery and the timber roof which covers them. The whole design is one that exhibits a good deal of massive wall space, and an eye not quick to recognise leading structural features might not readily  perceive that this is really a building whose stability resides not in its walls, but in its framework.

Early in the thirteenth century the original vaults of this nave, which had been completed in the preceding century, were damaged by fire and had to be repaired. It would appear, indeed, that their lateral cells were wholly reconstructed and somewhat changed in form; for the longitudinal arches of the original cells which remain in place fall considerably below the present vault surfaces, as may be seen in Fig. 46. Contemporaneously with this repairing and remodelling of these nave vaults great changes were making in other parts of the building—chiefly in the clerestory—in conformity with developments that had elsewhere taken place. These developments consisted chiefly in the enlargement of apertures, and in the dividing of them by mullions and simple forms of tracery. The apertures of the