exquisite effect of varied half shades, which are admirably set off by the telling darks of the deeper recesses.
FIG. 137.At Amiens this profile is employed for both transverse and diagonal ribs; and these ribs being of different magnitudes, and the parts of each being of appropriate scale, good proportion is established in the total effect, as it is with the different profile in the Cathedral of Paris.
The rib profile of Amiens was widely adopted, and was not materially altered during the best period of Gothic art, though in its proportions and in minor details it varied in different buildings. The profile b, Fig. 136, from the Cathedral of Beauvais, for instance, illustrates one of these variations. A comparatively unusual and certainly not a graceful modification of the square section is that shown at c, Fig. 136, from the small Church of Villeneuve sur Verberie (Oise). From about 1225 the square section fell into disuse in vault ribs, though it was still employed in the great ground-story arcades, as at Amiens and Beauvais.
The form of the Amiens rib led to a corresponding adjustment of the supporting capitals. When, in early Gothic vaults, the diagonal ribs had been of the section shown at c, Fig. 134, 
FIG. 138.the arrangement of the sustaining abaci was that shown in Fig. 137, from the triforium of Senlis. With the employment of the square section for all the ribs the arrangement became like that in the Cathedral of Paris, Fig. 22, p. 56. But with the new rib profile of Amiens the lateral abaci were again, as at Senlis, set even with the wall, while the central one assumed the diagonal position, as in Fig. 138.
