This was, however, lost in English works on the introduction of the circular abacus, and I must say that much expression and emphasis was lost with it. Not only, indeed, did the abacus in French work face or point in the direction of the arched rib, but its plan was often made to fit to it in the most direct manner, and even the direction of the principal stalks of the foliage had reference to the supported rib (Fig. 148). [Illustration: Fig. 148.--Laon Cathedral. Respond in Choir Aisle.] The system of moulding, again, follows out the same laws of reason. An arch-moulding, for instance, is founded on what is supposed to be the original section of the order or rib. Thus, if the normal section of the rib be square, the section of the mouldings is made to fit to that figure (Fig. 149); if chamfered or a part of an octagon, the mouldings, again, fit to it (Fig. 150); the abacus in each case taking the normal plan of the ribs. [Illustration: Fig. 149.] [Illustration: Fig. 150.] [Illustration: Fig. 151.] As to æsthetical forms, the mouldings were studiously arranged so as to produce in some parts the greatest contrasts, in others the most elegant gradations of light and shade. The heaviness of large roll mouldings was often relieved by fillets or by raised edges or “keels,” by which diversity was gained without loss of mass (Fig. 151). Hollows, again, were relieved by the insertion of sparkling ornaments, such as the toothed ornament, the rosette, the ball-flower, the four-leaved flower, and many others; and in other instances by the introduction of bands of foliage. The sections of moulding differed entirely from those of Roman architecture, being far more free and less mechanical, and at once more delicate in feeling and more carefully studied with reference to light and shade. They resembled Greek mouldings, in fact, far more than Roman. Enriched mouldings differed from the usual practice in antique work in this respect, that the enrichment was added to instead of being cut out of the original moulding; its practical use being to strengthen the hollows rather then to enrich the rounds. In this respect the practice of the Romanesque builder had been different; and perhaps a union of the two systems would be better than a close adherence to either.