VI. CURVILINEAR.—But the great building period at Bristol was between 1315 and 1349—that short but brilliant period when English mediæval design was at its best—which culminated in the Octagon and Lady chapel of Ely, the choir-screens of Southwell and Lincoln, and the Percy monument at Beverley. Everything east of the nave was pulled down and rebuilt _de novo_. And a very remarkable design it is; in fact, quite unique among our cathedrals. All other cathedral authorities had agreed long ago that the cardinal fault in all Romanesque design was its bad system of lighting, but that the remedy was to be found mainly in improving the top-lighting—_i.e._, in increasing the dimensions of the clerestory. Beverley clerestory had taller windows than Durham; Salisbury clerestory had three windows for every one of Beverley; Exeter spread out its windows in increasing breadth till they touched the buttresses on either side; the clerestories of the choir of Gloucester, now in course of erection, were a vast, lofty, continuous sheet of glass. But there was an alternative system of improving the lighting, which in many large churches, such as Grantham, Ledbury, and Leominster, was the result of fortuitous growth, but which in the choir of the Temple Church, London, and in Patrington Church now in course of erection, was the result of deliberate design. It was to magnify the aisles at the expense of the nave, to lift them up so high that windows of vast height could be placed in their walls, to dispense with a clerestory altogether, and to give to the pier-arcade of the nave the additional height gained by the suppression of the clerestory. It was to substitute side-lighting for top-lighting; to rely exclusively on the flood of light passing from vast, lofty aisle windows into the nave through its elevated arches. Hence the big windows of Bristol choir, each representing a pair of windows; the lower half the usual small window of an aisle, the upper half the larger window stolen from the clerestory. [Illustration: BERKELEY CHAPEL.]