266 COMPARATIVE ARCHITECTURE. corbels (Nos. 105 d and 107 e). Owing to the smallness of scale this favourite feature may be considered as a string course or cornice. Open arcades, the origin of which have already been dealt with (page 237), occur under the eaves of roofs, especially round the apses (Nos. 104 and 106). The churches have sometimes a triforium and always a clerestory. c. Openings. — No tendency towards tracery is found. The windows are usually single, being rarely grouped (No. 106). The doorways (Nos. 105 and 107 n) are placed at the side, rarely in the west front or transept ends. D. Roofs. — In the Rhine district a central semicircular barrel vault was supported by half-barrel vaults over the aisles, a system which led by degrees to complete Gothic vaulting. Timber roofs were also employed for large spans. Tower roofs, and spires of curious form, are a special feature of the style. A gable on each tower face, with high pitched intersecting roofs (No. 107 g), is common, the latter being formed by the intersections of the planes between the adjacent sides of adjoining gables forming a pyramid, being a step in the evolution of spire growth. E. Columns. — The nave arcades were generally constructed of square piers, with half columns attached, and the alternation of piers and columns is a favourite German feature. The capitals (No. 107 c, D, F, h), though bold in execution, are well designed, being superior to the later Gothic examples. F. Mouldings (see Walls). — These are as a rule of indifferent design, but the capitals and bases take a distinctive form, leading from Roman through Romanesque to Gothic. G. Ornament. — Internally the flat plain surfaces were occa- sionally decorated in fresco, and the traditions and examples of the early Christian and Byzantine mosaic decorations, were carried on in color. In the north colored bricks were used, and were unsuitable for rich decoration, thus accounting for the absence of sculptured foliage. 5. REFERENCE BOOKS. Boisseree (S.). — " Denkmale der Baukunstain Nieder-Rhein." Folio. Munich, 1844. Moller(G.). — " Denkinaeler der Deutschen Baukunst." Folio. Leipzig. 1852. Hardy (A. S.). — " Passe Rose" (Historical Novel).
