FIG. 120.—ONE BAY, ABBEY OF ST. DENIS.

INTERIOR DESIGN. The progressive change outlined in the last chapter, by which the wall was practically suppressed, the windows correspondingly enlarged, and every part of the structure made loftier and more slender, resulted in the evolution of a system of interior design well represented by the nave of Amiens. The second story or gallery over the side aisle disappeared, but the aisle itself was very high. The triforium was no longer a gallery, but a richly arcaded passage in the thickness of the wall, corresponding to the roofing-space over the aisle, and generally treated like a lower stage of the clearstory. Nearly the whole space above it was occupied in each bay by the vast clearstory window filled with simple but effective geometric tracery over slender mullions. The side aisles were lighted by windows which, like those in the clearstory, occupied nearly the whole available wall-space under the vaulting. The piers and shafts were all clustered and remarkably slender. The whole construction of this vast edifice, which covers nearly eighty thousand square feet, is a marvel of lightness, of scientific combinations, and of fine execution. Its great vault rises to a height of one hundred and forty feet. The nave of St. Denis, though less lofty, resembles it closely in style (Fig. 120). Earlier cathedrals show less of the harmony of proportion, the perfect working out of the relation of all parts of the composition of each bay, so conspicuous in the Amiens type, which was followed in most of the later churches.

WINDOWS: TRACERY. The clearstory windows of Noyon, Soissons, Sens, and the choir of Vézelay (1200) were simple arched openings arranged singly, in pairs, or in threes. In the cathedral of Chartres (1194–1220) they consist of two arched windows with a circle above them, forming a sort of plate tracery under a single arch. In the chapel windows of the choir at Reims (1215) the tracery of mullions and circles was moulded inside and out, and the intermediate triangular spaces all pierced and glazed. Rose windows were early used in front and transept façades. During the thirteenth and fourteenth centuries they were made of vast size and great lightness of tracery, as in the transepts of Notre Dame (1257) and the west front of Amiens (1288). From the design of these windows is derived the name Rayonnant, often applied to the French Gothic style of the period 1275–1375.

FIG. 121.—THE STE. CHAPELLE, PARIS.

THE SAINTE CHAPELLE. In this beautiful royal chapel at Paris, built 1242–47, Gothic design was admirably exemplified in the noble windows 15 by 50 feet in size, which perhaps furnished the models for those of Amiens and St. Denis. Each was divided by slender mullions into four lancet-like lights gathered under the rich tracery of the window-head. They were filled with stained glass of the most brilliant but harmonious hues. They occupy the whole available wall-space, so that the ribbed vault internally seems almost to rest on walls of glass, so slender are the visible supports and so effaced by the glow of color in the windows. Certainly lightness of construction and the suppression of the wall-masonry could hardly be carried further than here (Fig. 121). Among other chapels of the same type are those in the palace of St. Germain-en-Laye (1240), and a later example in the château of Vincennes, begun by Charles VI., but not finished till 1525.