+SCALE.+ The French cathedrals were nearly all of imposing dimensions. Noyon, one of the smallest, is 333 feet long; Sens measures 354. Laon, Bourges, Troyes, Notre Dame, Le Mans, Rouen, and Chartres vary from 396 to 437 feet in extreme length; Reims measures 483, and Amiens, the longest of all, 521 feet. Notre Dame is 124 feet wide across the five aisles of the nave; Bourges, somewhat wider. The central aisles of these two cathedrals, and of Laon, Amiens, and Beauvais, have a span of not far from 40 feet from centre to centre of the piers; while the ridge of the vaulting, which in Notre Dame is 108 feet above the pavement, and in Bourges 125, reaches in Amiens a height of 140 feet, and of nearly 160 in Beauvais. This emphasis of the height, from 3 to 3½ times the clear width of the nave or choir, is one of the most striking features of the French cathedrals. It produces an impressive effect, but tends to dwarf the great width of the central aisle. +EXTERIOR DESIGN.+ Here, as in the interior, every feature had its constructive _raison d’être_, and the total effect was determined by the fundamental structural scheme. This was especially true of the lateral elevations, in which the pinnacled buttresses, the flying arches, and the traceried windows of the side aisle and clearstory, repeated uniformly at each bay, were the principal elements of the design. The transept façades and main front allowed greater scope for invention and fancy, but even here the interior membering gave the key to the composition. Strong buttresses marked the division of the aisles and resisted the thrust of the terminal pier arches, and rose windows filled the greater part of the wall space under the end of the lofty vaulting. The whole structure was crowned by a steep-pitched roof of wood, covered with lead, copper, or tiles, to protect the vault from damage by snow and moisture. This roof occasioned the steep gables which crowned the transept and main façades. The main front was frequently adorned, above the triple portal, with a gallery of niches or tabernacles filled with statues of kings. Different types of composition are represented by Chartres, Notre Dame, Amiens, Reims, and Rouen, of which Notre Dame (Fig. 124) and Reims are perhaps the finest. Notre Dame is especially remarkable for its stately simplicity and the even balancing of horizontal and vertical elements. [Illustration: FIG. 124.--WEST FRONT OF NOTRE DAME, PARIS.] [Illustration: FIG. 125.--WEST FRONT OF ST. MACLOU, ROUEN.]