These devices all answered perfectly so long as the space to be roofed was square, or nearly so; but when this mode of vaulting came to be applied to the bays of the central nave, which were twice as long in one direction as in the other, the difficulties seemed insuperable. By cutting off the angle as in the former instance (as at B, fig. 2, Woodcut No. 814), you may get either a small diamond-shaped space in the centre or a square, but in both cases the pyramid becomes very awkward; and by carrying on the system as before, you never arrive at a circle, but at an elliptical section as shown at D, fig. 2 (Woodcut No. 814). [Illustration: 815. Vault of Cloister, Gloucester.] The builders of King’s College Chapel strove to obviate the difficulty by continuing the conoid to the centre, and then cutting off what was redundant at the sides, as in E, fig. 2, or, as shown in the view of the interior (Woodcut No. 846) further on. The richness of the ornaments, and the loftiness and elegance of the whole, lead us to overlook these defects at Cambridge, but nothing can be less constructive or less pleasing that the abruptness of the intersections so obtained. In the central aisle of Henry VII.’s Chapel it was avoided by a bold series of pendants, supported by internal flying buttresses, producing a surprising degree of complexity, and such an exhibition of mechanical dexterity as never fails to astonish, and generally to please; though it must be confessed that it is at best a mere piece of ingenuity very unworthy of English art. By far the most satisfactory of these roofs is that at Windsor, where a broad flat band is introduced in the centre of the roof, throughout the whole length of the chapel. This is ornamented by panelling of the most exquisite design, and relieved by pendants of slight projection, the whole being in such good taste as to make it one of the richest and probably the most beautiful vault ever constructed. It has not the loftiness of that at Cambridge, being only 52 ft. high, instead of 78, nor is it of the same extent, and consequently it does not so immediately strike observers, but on examination it is far more satisfactory. [Illustration: 816. Vault of Aisle at St. George’s, Windsor.] [Illustration: 817. Aisle in Henry VII.’s Chapel, Westminster.] [Illustration: 818. Retro-choir, Peterborough Cathedral. (Cath. Hb.)]