Chap. II.

VAULTR.

883

713. Yault. of St. George's Chapel, Windsor. From Britton.

circles so as to confuse and deceive the eye. At Windsor the defect
was ohviated hy using a low four-centred arch invented for t.he pur-
pose, so that the outer tangent of the conoid was nearly flat, and the
rihs could he carried to the centre without heing hroken, as is shown
in woodcut No. 713. This may he considered the perfection of this
kind of vaulting, and
is perhaps the most
heautiful method ever
invented. At AVest-
minster the ditflculty
was got over hy revers-
ing the curve hy the
introduction of pen-
dants. This was a
clever expedient, and
a startling effect is
therehy produced, but
it is so evidently a tour
de force that the result
is never quite satisfac-
tory; still on a small
scale it was admissible.

These devices all
answered perfectly so
long as the space to
he roofed was square,
or nearly so ; hut when
this mode of vaulting
came to he applied to
the hays of the central
aisle, which were twice
as long in one direction
as in the other, the dif-
ficulties seemed insu-
perahle. By cutting
off the angle as in the
former instance (as at
b, fig. 2, woodcut No.

711), you may get
either a small dia-
mond-shaped space in
the centre or a square,
hut in hoth cases a very
awkward pyramid; and carrying on that system to the curvilinear,
you never arrive at a circle, hut at an elliptical section, as shown in
woodcut No. 711, at d, fig. 2.

The huilders of King’s College Chapel strove to obviate the diffi-
culty hy continuing the eonoid to the centre, and t.hen cutting off what
was redundant at, the sides, as in e, fig. 2.

714. Aisle in Henry VII.’s Chapel, Westminster.