At Soissons is a window in which the interspaces between the medallions are filled with deep blue, broken only here and there by a spot of ruby; at Poitiers also the ornament in spandrils is often just a quatrefoil or so, barely foliated, if at all; at Bourges there is an instance of spandrils ([page 125]) occupied by bare curling stalks and rosette-like flowers; at Poitiers the bands which frame the medallions have a way of interlacing, not in the simple fashion shown in the example from Canterbury [below], but so as to form a kind of pattern in the spandrils in front of the geometric filling; and there are other variations on the accustomed medallion tunes; but as a rule the ornament consists either of the usual Early Gothic foliation, closely akin to that in the borders, such as is shown on [pages 129], [130], [328], [330], or of geometric pattern, such as is here given. The rarity of the mosaic diaper in this country may be gathered from the fact that in the whole series of Early medallion windows at Canterbury it is found only once, its frequency in France from the fact that in the choir alone of Bourges Cathedral it occurs in no less than twenty-two instances; again at Chartres, out of twenty-seven great windows, not more than four have scrollwork; at Poitiers, on the other hand, there is little geometric diaper, but the ornament is of the simplest, and barely foliated. This device of geometric diaper-filling was possibly inspired by the idea of utilising the small chips of precious glass, which, with the then method of working, must have accumulated in great quantity. In any case, it must have been encouraged by that consideration, if not actually suggested by it. Apart from economy, which is a condition of craftsmanlike work, there does seem a sort of artistic logic in the use of merely geometric design for quite subordinate filling, to act as a foil to figure work; but there was no occasion to put the mosaic of fragments quite so regularly, not to say mechanically, together, as was the custom to do.
80. French Mosaic Diapers.
That is shown in a rather unusual instance in a window of the Lower Church at Assisi; there occurs there a diaper of circles with blue interstices, where the circles, though all alike painted with a star pattern, vary in colour in a seemingly accidental way, and are red, yellow, green, brown, just as it took the fancy of the glazier.
81. DETAIL OF MEDALLION WINDOW, CANTERBURY.
It follows inevitably from the small scale on which these patterns are set out, and from the radiation of the coloured light, that unless very great discretion is exercised the rays get mixed, with a result which is often the reverse of pleasing. And the worst of it was that the French glaziers particularly affectioned a combination of red and blue most difficult to manage. A very favourite pattern consisted of cross bands of ruby (as [above]), enclosing squares or diamonds of blue, with dots of white at the intersection of the ruby bands, which persists always in running to purple.