ARCHITECTURE. 157 
the whole group an arched outline; and this was indicated by an arched 
drip-mould or label. It then became desirable to lighten the irregular. 
shaped masses of stone left between the perforations, and this was done 
by piercing these masses or spandrils, and reducing the solid frame of each 
foil or rosette to an equal thickness all round, as if several such frames or 
rings were packed into one great arched opening, which henceforth was 
regarded as one window instead of several. 
The oldest windows are generally round-arched and more or less simple, 
as shown in pl. 39, jigs. 82-36. Coupled windows (jig. 37) occur only in 
the first centuries of the middle ages. Among the earliest packed windows 
were those represented in pl. 40, jig. 9, consisting of three round-arched 
windows, the central one of greater width, with a common arch sprung 
over them all. The first round windows are of the same age, and occur 
between the heads of two coupled windows (pl. 34, jig. 25), but never 
alone. At a later period large rosette windows occur alone in the principal 
facades of churches, divided by little columns set around the centre like 
wheel spokes, and connected by round or trefoil arches (pl. 39, fig. 88). In 
the pointed-arch style the rosette window is always surmounted by an arch, 
or at least a drip-mould. 
The improvement of the windows in the pointed style was as gradual as 
that in the Romanesque and Byzantine. We first find them small and 
simple (pl. 40, jig. 14); then coupled (jig. 15); next coupled with a perfo- 
rated foil rosette between their heads (jig. 16); then the same arrangement 
packed into a common arch resting on columns (pl. 39, fig. 40). The 
desire for greater ornament made the windows more and more complicated, 
and designing the patterns for windows became a special art, the art of 
tracery. One centre mullion not being found sufficient to admit of many 
variations of design, three, five, and even seven were introduced. The 
mullions are usually perpendicular up to the level of the springings of the 
arch, where they diverge into arches, curves, and flowing lines, enriched 
with foliations. Pl. 40, fig. 17, gives an example of a window with three 
mullions; pl. 39, fig. 41, with five; and jig. 42 with seven. The division 
of the heads of the arches in these examples is strictly geometrical ; the 
principal groups are separate, and each has its own appropriate subdivisions 
and ornaments. 
The strictly geometrical tracery was in the 15th century superseded by 
the less beautiful but more lively English leaf tracery (pl. 40, fig. 20), and 
‘tthe still more lively French flamboyant tracery (jigs. 18,19; and pl. 39, 
jig. 39). According to Garbett’s Principles of Design in Architecture, the 
difference between the flamboyant and the English leaf tracery is, that 
while the upper ends of the English loops or leaves are round or simply 
pointed, 7. e. with final angles, the upper ends in France terminate, like the 
lower, in angles of contact (those formed by two curves that have a common 
tangent). It was necessary to the leafy effect that the lower angles should 
be tangential, but to the flame-like effect that the upper ones should be so, 
even if the lower were finite; and hence some examples of flamboyant 
tracery turned upside down form a kind of leaf tracery. 
157 
