How to Study Architecture

by Charles H. Caffin

In some instances a shaft was carried up from the intervening pier on each side of the nave, supporting an intermediate transverse arch, so that the vaulting became sexpartite, or divided into six compartments. Whether the bay were six part or four part, the curve of all the groins—longitudinal, transverse, and diagonal—were semicircular. Accordingly, since the diagonals had a longer diameter, their curves rose above the others. This variation was met by giving a concave or domelike surface to each of the compartments, so that the workmen were able to adjust the stones to the differences of the curves.

Rib-vaulting.—While this was possible in the actual operation of placing the stones, it would have needed exceedingly delicate calculation to build timber centering adjusted in advance to these domelike surfaces. Moreover, the ponderousness of the dome nave vaulting had made the use of timber centering extremely costly, even where timber was plentiful; while in districts sparsely supplied the cost had been prohibitive. Consequently, the ingenuity of the builders devised a system of construction that reduced the need of timber centering to a minimum. This was the system known as rib-vaulting. Briefly, it consisted in spanning the space—longitudinally, transversely, and diagonally—with preliminary arches of masonry, thus forming a skeleton frame composed of what are known as ribs. Each of these ribs, being comparatively light, could be constructed on a single moveable and expansible piece of centering, called a cerce. When the ribs had set, they offered sufficient support to hold up the doming of the compartments while it was being laid.

To some extent this method of construction had been anticipated by the Romans who in certain instances built preliminary transverse ribs to act as permanent centerings of the vault, in the masonry of which the ribs were buried from sight. The reintroduction of this device and its further development, as above described, originated with the Lombard architects. This has been definitely determined by the English architect, Arthur Kingsley Porter, who has proved that the adoption of the system was prompted by the scarcity of wood in this locality. From Italy it spread to France, where it made its appearance in the Ile de France about 1100 or some 60 years after its adoption in Lombardy. It was at first employed purely as a necessary constructive expedient. Later its æsthetic possibilities came to be recognised, and the rib was developed by the Gothic architects into an element of great beauty, one of the characteristic features of the Gothic style.

Meanwhile, the use of vaulting by the Romanesque architects affected the character of the exterior. Mention has already been made of the masonry piers and the massive outside walls, pierced with small windows. For the further support of the vaulting-thrust towers were freely used. While in Italy the campanile was frequently detached from the main edifice, the towers in western and northern Romanesque churches became elements of prominence in the design. A pair frequently flanked the apse or four rose in the angles of the transepts and choir, while another pair, sometimes connected by a gallery, flanked the west end. A tower or dome might also surmount the crossing of the nave and transepts. The towers were square, polygonal, or circular, divided into stories which were pierced with windows or embellished with arcades. They were crowned, like the nave and aisles, with an exterior sloping roof.

Arcading.—The arcading, which now became a favourite method of embellishing walls, was of two kinds; either being open and permitting a passageway at the back of them, or with columns and arch mouldings attached to the wall, in the manner known as blind arcading. Another feature for strengthening as well as embellishing the wall was the use of masonry piers, which, resting on a plinth, projected from the wall only as far as the width of the cornice.

The exteriors, in fact, were no longer, as in early Christian churches, plain and almost barn-like, but assumed a varied picturesqueness that, however, was distinguished by a fine structural unity.

The arch, whether used in interior or exterior arcading or for the tops of doors and windows, was round; usually semicircular but occasionally stilted, the ends of the semicircle, that is to say, being raised on perpendicular lines. The later introduction of the pointed arch, it may be added, marks the transition from Romanesque to Gothic.

A characteristic development of the Romanesque style is the treatment of the doors and windows. The jambs or sides were carried back in a series of angular recesses, which were filled with small columns, whose abaci frequently united in a continuous moulding. In many cases the angular recesses of the jambs were prolonged around the arch.

The shafts of columns were decorated with fluting, which might be perpendicular, spiral, or barred like trellis-work. The capitals, except when antique Corinthian or Ionic columns were utilised, display a variety of embellishments, sometimes influenced by Byzantine examples, at other times representing an original working out of foliage motives, often rude in treatment, but, especially in the German work, vigorously decorative.

In the nave arcading, that is to say the series of arches on each side of the nave, the supports consisted of square piers, to the faces of which columns were attached. From two of them sprang the arches; a third supported the vaulting of the aisles, while a fourth was run up to a higher level to carry the vaulting of the nave.