Lectures on the rise and development of medieval architecture; vol. 2

by Sir George Gilbert Scott

These earnest and restless strivings, however, had the effect of rendering apparent to them a defect, both structural and artistic, in the conditions prescribed by a round-arched style. They had freed themselves from the trammels of the arbitrary rules of proportion, and might render their structures lofty or the reverse at pleasure: their columns might be as short and sturdy as the most archaic Doric, or might outdo the most elegant Corinthian in the lightness of their proportions; yet the arch they were condemned to carry was limited in height to one-half of its own diameter; or, if allowed to exceed this, by means of stilting, this was evidently but a clumsy expedient, and only suited to particular positions.

The whole tendency, too, of the onward movement of the art was towards increased height; and, while walls and pillars might avail themselves to the full of this upward striving, it was hard that the arch—the very essence of the style—should be condemned to unalterable stuntiness. Proportion evidently claimed that the arch should have its fair share in the increasing height of the buildings, yet the inexorable semicircle said, “Nay, my proportions are fixed. You may lengthen your straight lines as you please; but by no law of science can my height exceed one-half of my width.”

A geometrician might reply that the semicircle might be stretched upwards into a semi-ellipse with its major axis upright. I do not think that our Mediæval builders ever tried this dismal experiment, nor do I know that it was ever attempted, except by the barbarous Parthians, in a building you will find figured in Mr. Fergusson’s Handbook; and so hideous was the result that one may well suppose it to have been handed down as a warning to subsequent generations!

Nor was this craving after a loftier arch the result of taste alone. Constructive motives pointed in the same direction; for it was found that round arches, when carrying great loads, as those sustaining towers, etc., were apt to overcome the resistance of their piers; and many failures were the result. The same was found to result from vaulting over wide spaces. True it is that the Romans, in the great halls of their baths, had vaulted over spans of double the width of the naves of our Norman cathedrals; but this had been effected at the expense of the utility of their aisles, which were cut up into short lengths by the ponderous abutments needed to sustain the tremendous pressure of the central vault. Besides which, the Mediæval builders aimed at raising the springing of these vaulted naves to a height out of the reach of the abutment of the aisles. An arch of less lateral pressure was therefore desired.

Another motive might have led to a similar aim. We have seen what difficulties and contrivances resulted from the exigencies of vaulting over irregular spaces where it was desirable that the crowns and springers of the surrounding arches should range on the same levels, though their spans might differ to any extent. It was clear, then, that an arch of more elastic proportions was the grand desideratum.

The claims, then, of proportion, of construction, and of geometrical convenience, all took the same direction, and demanded an arch of variable proportions.

This three-fold demand was met by the introduction of the Pointed arch.

To apply this to our main subject of vaulting, we at once see that, in addition to constructive advantages, the arch could now he proportioned in height to its supporting piers, and the unequal sides of the vaulted spaces could now be arched in such a manner as to satisfy the exigencies of the vaulting without the necessity of resorting to awkward contrivances; so that an accession was obtained at once of strength, beauty, and facility of application.

I have called the use of diagonal ribs the Magna Charta of the art of vaulting; but it must share this honour with the Pointed arch. Let us now proceed to trace the progress of the art under this double charter of liberty.

The first introduction of the Pointed arch into vaulting seems to have been made without a full consciousness of its advantages, and rather with a view to strength and general beauty than to the convenience of covering irregular spaces, for in many early specimens—as originally in the Cathedral of Sens,[46] and in the work of William of Sens at Canterbury,[47]—the round arch continued to be used in the narrow bay against the walls, while the pointed arch was used for the wider spans. In nearly all English specimens, however, full advantage was at once taken of the newly-attained freedom: thus, at St. Joseph’s Chapel, at Glastonbury,—a work otherwise purely round-arched,—the groining assumes throughout the pointed form, the narrow bays being especially acute.[48] The same is the case at St. Cross, another very early transitional work,[49] and in the nave and transepts of St. David’s Cathedral[50] (erected about 1180), though the groining was never carried out, we have the preparations for it with pointed wall-ribs in the sides, while the round arch is mainly used beneath. I shall, therefore, disregard this occasional inconsistency.