Under such impressions, when the architect contemplated the ancient structures, the principle of convenience would at once suggest the necessity of heightening their low arches, and decreasing their enormous supports, by which light was obstructed, and space filled up. He saw, however, these efforts could not be accomplished on the old methods:--here the principle of stability--no abstract theory, but the knowledge of the practical builder--taught him, that by elevating the crown of the arch, and thus removing in part the lateral pressure, both objects would be accomplished; for while height was gained, the weight would be thrown more into the perpendicular, and consequently would remain firm with diminished support. The principle once introduced, was carried even to frightful boldness. But again, though the lateral pressure was removed from the arcade itself, abutment was still to be provided at the extremities and side-walls. Hence the peculiar characteristic of the buttress. This indeed existed in the old Gothic; but here the feature assumed a novel appearance. The arches being placed high, required additional altitude to be added, as a counterbalance, at the opposing point; thus the buttress was converted into a turret or pinnacle, susceptible of every varied form which it afterwards received, when the desire of ornament, without the guidance of taste, wandered into every maze of fantasy. Thus the whole system depended upon principle--neither rising, like an exhalation, in consequence of imported knowledge, nor emulating some remote association or model, but by the slow and gradual process of experience.