214 COMPARATIVE ARCHITECTURE. E. Columns. — In the earlier buildings, these were taken from ancient structures, which not being so numerous in the East as in the neighbourhood of Rome, the supply was sooner exhausted ; and thus there was an incentive to design fresh ones. Capitals sometimes took a form derived from the Roman Ionic (No. 89 c) or Corinthian types (Nos. 88 and 8g d), or consisted in the lower portion of a cube block with rounded corners, over which was placed a deep abacus block, sometimes called a " dosseret " (No. 89 D, e). This represented the disused Classic architrave, and aided in supporting the springing of the arch, which was larger in area than the shaft of the column. Further, an altered shape of capital was required to support the arch, a convex form being best adapted. The surfaces of these capitals were carved with incised foliage of sharp outline, having drilled eyes (No. 88) between the leaves. Several other types are shown in No. 89. Columns were used constructively, but were always subordinate features, and often only introduced to support galleries, the massive piers alone supporting the superstructure. F. Mouldings. — These were unimportant, their place being taken by broad flat expanses of wall surfaces. Internally, the decorative lining of marble and mosaic in panels was sometimes framed in billet mouldings, probably derived from the Classic dentils, and flat splays enriched by incised ornamentation were used. Externally, the simple treatment of the elevations in flat expanses of brickwork, with occasional stone banded courses, did not leave the same scope for mouldings as in other styles. G. Ornament. — The scheme of ornamentation was elaborate in the extreme, the walls being lined with costly marbles with the veining carefully arranged so as to form patterns, and the vaults and upper part of walls with glass mosaic having symbolic figures, groups of saints and representations of the peacock (the emblem of immortal life), the whole forming a striking contrast to the less permanent painted frescoes usually adopted in the Western Romanesque churches (page 227). Mosaic thus was used in a broad way as a complete lining to a rough structure, and architectural lines were replaced by deco- rative bands in the mosaic. One surface melts into another as the mosaic sheet creeps from wall, arch, and pendentive up to the dome, and the gold surfaces being continued as a background to the figures, unity of surface is always maintained. Greek rather than Roman technique was followed in the carving, due to the origin of the craftsmen. The carving was mainly executed in low relief, and effect was frequently obtained by sinking portions of the surfaces. A special character of the carving was due to the use of the drill instead of the chisel (No. 88). The acanthus leaf, deeply channelled, and of V-shaped section, is
