Of all the exterior, only the tower and the façade showed during the transitional period a development to correspond with the vast changes that had been wrought in the interior of the edifice. Flying buttresses appeared commonly only in the last twenty years of the XII century, and up to that time, save perhaps for an occasional pointed arch, or a deeper buttress here and there, the exterior of the main body of the church remained essentially Romanesque in appearance. As early as 1140, however, the façades of great churches like St. Denis (Ill. 191) or Chartres1 (Ill. 190) began to show a changed character, the old Carolingian idea of flanking the central gable on either side by towers being developed into a new significance. The façade of Sens (Ill. 192), which retains some transitional fragments, is of interest for the arcade or gallery that seems to have been carried across it; - a feature which was nobly developed in the Gothic period. The builders of the Ile de France also employed a type of façade we have studied in Normandy, the central gable being flanked by turrets in lieu of towers. On the other hand, in country edifices they often accepted the somewhat awkward section of a three-aisled church without making any attempt to soften the outlines (Ill. 193).

In the treatment of the plan, outside of the addition and development of the ambulatory already described, few changes were introduced during the transitional era. Dimensions came to be greatly enlarged, but the typical dispositions were only slightly varied. Semicircular transept-ends were introduced at Noyon (Ill. 176), perhaps from Germany, and this singular motive was afterwards repeated in the south transept at Soissons and in the flamboyant period in the XV century church of Neufchâtel (Seine-Inférieure). The plan of Noyon (Ill. 176) is also peculiar for a second transept introduced at the west end adjoining the façade - a disposition of interest as finding analogies in England.2

Cloisters were doubtless constructed at this time in France in connection with all cathedral and abbey churches, but these

1 It should, of course, be remembered that only the lower portions of the façade of Chartres, together with the southern tower, date from this period.

2 e. g. at Ely. A western transept was planned at St. Germer but was never carried out.

lovely courts became the special object of attack in the Revolution and other iconoclastic periods of French history, with the result that practically all examples, whether of the transitional or Gothic epoch, have entirely disappeared. Fragments survive at Noyon, St. Jean-des-Vignes of Soissons and elsewhere; but I can not name a single well-preserved cloister nearer the Ile de France than Mt.-St.-Michel, a monument which is much more English than French in style. Consequently we can only imagine, on analogy with cloisters in other countries, especially England, what the cloister of the Ile de France must have been.

While thus the changes wrought in the exterior of the design apart from the rib vault and its corollaries were few, there was only one new feature of importance independent of that allcontrolling principle introduced in the interior. It has been seen that the habit of building high triforium galleries had been introduced from Normandy at St. Denis. Now the introduction of this gallery led to a noteworthy innovation in design. Since the triforium arcade had always been used to occupy the wall space beneath the lean-to roof of the aisles, when this roof was placed above the gallery, it was natural to place here also the triforium arcade, even though a triforium gallery already existed below (Ill. 173). Hence it resulted that the nave was divided into four stories: the main arcade, the gallery, the triforium, and the clearstory. The effect of this fourfold design, as may be seen in the illustrations of the naves of Noyon (Ill. 180), of Notre Dame of Châlons-sur-Marne (Ill. 182), and of St. Remi of Reims (Ill. 183), was not altogether happy. It tended to multiply the horizontal lines, whereas the true destiny of Gothic lay in the emphasis of the vertical line. However, doubtless owing to the fact that it tended to raise high the concealed flying buttresses, the four-storied design was very generally employed in the larger monuments of the second phase of the transition.

In the choir of St. Remi (Ill. 183) an attempt was made, while preserving the four-storied design, to overcome the effects

1 The most ancient cloister extant in Normandy is, I believe, that of Abbaye Blanche of Mortain, dating from the end of the XII century.

of the extra horizontal lines, by binding together into one composition clearstory and triforium. This experiment which had already been tried at St. Germain-des-Prés and at Cambronne was so successful, that it was later borrowed in the nave of Amiens, and formed the basis of the glazed triforiums of the rayonnant period.

In Gothic architecture structure is so ornamental, and ornament is so structural, that it is impossible to draw a sharp line between the essential body of the building and its applied decoration. As Romanesque ornament was transformed by almost imperceptible stages into Gothic ornament, the forms which had hitherto had little but purely decorative significance, at once commenced to assume a share, however modest, in the task of holding the building together.

This is most strikingly illustrated in the profiles of mouldings, features which had always been the most purely esthetic and decorative part of a building, but which in the transitional period came to assume distinctly structural functions. Such structural mouldings are found in the abaci and bases of piers, in interior and exterior string-courses and cornices, in the archivolts of arches, windows, and doorways, and in the transverse and diagonal vaulting ribs. The variety and combinations of profiles used in each of these positions is legion, and it would be well-nigh impossible to exhaust all the various types. Yet amid all this infinite variety of design, this exuberance of invention, there are none the less certain governing structural principles. The artists who designed and executed these profiles possessed a fertile imagination which was restrained solely by the dictates of structural truth and expediency.

A capital, as I believe Viollet-le-Duc first pointed out, is of structural significance only when it serves to adjust a greater load to a more slender support. A Roman Corinthian colonnade would stand quite as well were the capitals omitted and the architrave placed directly on the shafts. On the other hand, if the capitals were omitted in a Byzantine or Gothic arch-construction such as, for example, the chevet of Noyon