ORIGIN AND CHARACTER. The constant striving of the architects of the eleventh and twelfth cen turies in France was to perfect a system of vault ing that should not enslave them to heavy walls or to narrow, low, and dark interiors. This could be done only by concentrating the horizontal, di agonal, and vertical strains and thrusts of the masonry entirely upon certain isolated points, and by balancing one by the other so as to produce a constructive skeleton in equilibrium. This was accomplished perfectly in Gothic architecture for the first time, though the principle itself was an old one. The ribs of Gothic vaulting, the piers that receive their downward pressures, the flying buttresses that take up and neutralize the hori zontal thrust, form a pyramidal skeleton that would stand uninjured if all the walls and vault ing were removed. The pointed arch was first used in the vaulting because it not only exerted less outward thrust with a given span (see Riss), but also made it possible to construct vaults of any height, and on any oblong plan, and thus gave elasticity of form. The pointed form passed
then to the next most constructive part of the church—the arches dividing nave and aisles, and the main doorways—and only later to the gal leries, windows, and decorative details. It is im portant to remember that the pointed arch used in the Mohammedan, Sicilian, Burgundian, and other schools has nothing to do with the Gothic style, which is a constructive style following cer tain definite principles. It is the only thoroughly scientific and logical style of architecture ever developed, one that was absolute master of all materials ; one in which nothing was left to chance or individual fancy. Its watchword was frankly to reveal its methods; every structural device showed. It did not spring at once into being, but was a gradual growth, involving, first, the inven tion of the means to effect constructive concentra tion and equilibrium; second, to develop the in fluence of these principles on architectural form; third, to give these forms the most artistic ex pression.