Another process was developed; namely, the use of enamel paint. A pigment composed of powdered coloured glass, mixed with some such binder as glue, was applied with a brush, after which the glass was subjected to a comparatively low degree of heat, sufficient to flux the pigment and fuse it into the body of the material. At first the only colour employed was brown, which being opaque in the firing was used for the line of the drawing. It was even used for shading, the paint being spread in gradations of thickness and, when dry, scraped off in parts or reduced to a stipple of tiny dots, by the action of a stiff brush. This process was also applied upon the yellow stain and comparatively colourless glass (grisaille) to produce diapers of pattern and other ornament.
Finally, about the beginning of the sixteenth century, enamel paints of other colours were employed, and painting upon glass marks the last stage in the European technique of window glass. While the colours, unlike the opaque brown, were translucent, they lacked the brilliance and purity as well as the richness and depth of pot metal. But by this time, as in other kinds of decoration, the designers were absorbed with details. A favourite task enforced upon them was the insertion of heraldic insignia in the windows, and brushwork was the only method that could reproduce the complicated devices of “quartering” the coats of arms. Window decoration, in fact, had ceased to be an art of glass work and become confused with the art of painting. The end of glass decoration was completed when the window was filled with rectangular panes of white glass, on which the painter depicted figures of saints or symbolical nymphs, as Sir Joshua Reynolds, for example, did in the windows of the ante-chapel of New College, Oxford. This masterpiece of the trivial is popular, but represents a debased taste, founded upon a complete ignorance of the glass-technique, for Sir Joshua called in to his assistance a china painter!
Vaulting.—The treatment of the roofing displays more variety in English Gothic than in French. Wooden ceilings, which we will return to presently, often replaced the vaulting and the latter also became distinguished by elements that were only sparingly, if at all, employed in France. The French, as we have noted, constructed the diagonal as well as the longitudinal and transverse ribs with pointed profiles, so that their vaults were domical. The English, on the contrary, frequently used the half-circle for the diagonal ribs. Thus the vaults have level tops or ridges, the latter being marked by ridge ribs.
Tiercerons.—In England, during the thirteenth century, as in France, the plain four-part ribbed vault was used, as in the naves of Salisbury and Gloucester, and the aisles of Peterborough. Toward the end of the century, however, came in the use of subordinate ribs, called tiercerons. These were introduced between the transverse and diagonal ribs, as may be seen in the nave vaulting of Westminster Abbey. Their purpose was to decrease the pressure on the main ribs, and for their own further security a ridge rib was employed for them to abut on at the top.
Liernes.—During the Decorated Period of the fourteenth century a new set of ribs were introduced, which were known as Liernes—holding or binding ribs. The name was applied to any rib, other than the ridge rib, that did not spring from an abacus. They were ornamental rather than constructional and were freely employed to form a network of geometric pattern over the vaulting. Meanwhile, although they increase the apparent complexity of the vaulting, the actual constructive plan of the latter is not affected and may be simply four part. Such multiplication of ribs reduced the size of the intervening spaces or panels, whence this kind of vaulting is sometimes called rib and panel. It is also named stellar vaulting from the star-shaped patterns produced by the ribs. Examples are to be found in the choirs of Gloucester, Wells, Ely, the nave of Tewkesbury Abbey, and the vaulting of Winchester Cathedral, as rebuilt by William of Wykeham (1390).
Fan Vaulting.—The development of the Perpendicular Period or Fifteenth Century is that of Fan Vaulting, examples of which occur in Henry VII’s Chapel, Westminster; Divinity Schools, Oxford; King’s College Chapel, Cambridge; the retro-choir, Peterborough; Gloucester Cathedral, and St. George’s Chapel, Windsor. In this type of vaulting the ribs are all of equal curvature, and separated from one another by equal angles, terminating at the top in a circular ridge, which leaves a series of flat lozenge-shaped spaces.
Pendant Vaulting.—A further development, often used in connection with “Fan Vaulting,” as in Oxford Cathedral and Henry VII’s Chapel, is the device known as Pendant vaulting. It was at first adopted to sustain the flat spaces of the vaulting and consisted of a stone support suspended from an arch concealed above the vaulting. It was, in effect, a prolonged keystone, and its lowest part formed a base from which to build up. For by this time the old method of constructing ribs and laying panels upon them had been abandoned, and the vaulting was constructed of parts, interlocking like a Chinese puzzle.
A beautiful feature of English vaulting occurs in the polygonal Chapter Houses, in which the ribs radiate from a central column to the sides and angles of the polygon. “If these vaults are less majestic than domes of the same diameter, they are far more decorative and picturesque, while the Chapter Houses themselves were the most striking and original products of English Gothic. Every feature was designed with strict regard for the structural system determined by the admirable vaulting and the Sainte Chapelle was not more logical in its exemplification of Gothic principles.” (Hamlin.) Among the finest examples are those of Westminster, Wells, York, Lincoln, and Salisbury.
Open Wood Roofs.—The Saxon use of timber construction survived as a tradition and was developed by the Gothic builders, in the interior roofs that sheathed the vaulting and with specially fine effect in the ceiling-roofs of churches and halls. The simplest principle of it is the so-called tie-beam roof. In this, a succession of rafters slope up to each side of a ridge beam and are prevented from spreading by beams that tie them together at the foot. If the pitch of the roof were high, the construction would be strengthened by a post supported on the centre of the tie-beam, which is called a King-post. Instead of or in addition to this, two posts might be erected between the centre and the ends of the beams, known as Queen-posts. Each complete section of this arrangement is called a truss. It might be further stiffened by struts, that is to say cross pieces which, instead of tying the parts, keep them from being drawn together.
The next principle is the trussed-rafter or single-framed roof. Since the transverse beam might interfere with the vaulting, it was replaced by one or more cross-beams near the upper angle of the roof known as collars. These might be further stiffened by braces, fixed diagonally from the under side of the beam to the rafter. Further, short struts or upright posts might be added near the lower angles, connecting the rafters with short, horizontal pieces, attached to the ends of the rafters and resting on the wall. These were called sole-pieces and represent what would be left if the intermediate part of the tie-beam were sawn away. Sometimes an arched profile was secured by curving braces fixed to the rafters and collars. Or the collars were omitted and the curved braces were carried up to the ridge-beam, forming the variety of roof styled arch-braced. Frequently this style of roof was sheathed on its under side with boards decorated with ribs and bosses.