Bk. VI. Ch. 111. PIEK ARCHES. 151 change would have relieved its monotony without detracting from any of the excellent points of design it now possesses. The English arcliitects never attempted such vaults as those of Toulouse and Alby, 63 and 58 ft. respectively, still less such as that of Gerona in Spain, which is 72 ft. clear width. With our present mechanical knowledge, we could probably construct Avider vaults still. Even the Mediaeval architects in England might have done more hi this direction than they actually accomplished had they tried. On the whole, however, it seems that they exercised a wise discretion in liinitiniT themselves to moderate dimensions. More poetry of design and greater apparent size is attainable by the introduction of pillars on the floor, and with far less mechanical effort. Unless everything is increased in even a greater ratio, the dwarfing effect of a great vault never fails to make itself painfully apparent. We may regret that they did not vary their vaults by such an expedient as the lantern at Ely, but hardly that they confined them to the dimensions they generally adopted. PiEE Arches. Although the principles adopted by the English architects did not materially differ from those of their Continental confreres with regard to the arrangement of pier arches and the proportions of triforia and clerestories, still their practice was generally so sound and the results so satisfactory, that this seems the best i^lace to point out what the Mediaeval architects aimed at in the arrangement of their wall surfaces. In the Norman cathedrals the general scheme seems to have been to divide the height into three equ.al parts, and to allot one to the pier arch, another to the triforium or great gallery, and the third to the clerestory. In all the examjjles we now have, the upper is the smallest division ; but I cannot help fancying that some arrangement of the timbers of the roof gave the additional height required. It is generally supposed that the roof at Peterborough (Woodcut No. 574) was originally flat. This, however, is by no means clear, nor that it started so low ; but, be that as it may, the Avoodcut (No. 584) will explain the usual arrangement, as avcU as the changes afterwards introduced. At Winchester the two lower divisions are practically equal, the upper somewhat less, and the alternate arrangement of the piers hints at a hexapartite vault, if such should ever come to be executed. When William of Wykeham undertook to remodel the style of the nave, he first threw the two lower compartments into one, as shown on the left hand side of the cut. He then divided the whole height, as nearly as the masonry would allow him, into two equal parts, allotting one to the pier arches, and apportioning the upper as nearly as he could by giving two-thirds to the clerestory
