They had to work with a material which, being less scientifically compounded, was artistically immensely superior. In the manufacture of the old pot-metal something was left to Nature, much, that is to say, to accident. The colour, in other words, was not so evenly and exactly spread as by more modern processes. Being more unevenly distributed, it would frequently tone off at the edges, and the rays diffused from it would mingle in a softer harmony with those of the neighbouring coloured fragments. And greater variety was obtained, because a chemically imperfect process never gives two batches of glass from the pot quite alike. In early work, again, the fact that large pieces of glass could not be made was also on the side of the craftsmen. Perfect colour is the product of varied colours; the multiplicity of small pieces of glass set in deep black lines of lead yielded a result of rich, deep colouring, which is in the nature of things not to be obtained from one large sheet, however fine. But though the palette of the early glazier was so rich in quality with those splendid reds and ineffable blues, the secret of which has long been lost, and other primary colours, it was poor in extent. To this poverty must be ascribed the curious colouring of many details. Beards are often painted blue, and faces usually brown. Some shade of a rich purplish brown was in fact the ordinary flesh tint of the early glazier. In the window of the north transept, where S. Anne is portrayed, we have a very striking example of this. The brown face of S. Anne is there so large (it must be at least 2 feet in length), that the craftsman has been able to glaze it in several pieces. The eyes are of white, and so strongly leaded that they seem to stare out of the picture. The sunburnt effect of their brown visages only accentuates the Oriental aspect of many of these glass figures. As at Bourges, so here, the influence of the East is plainly visible, not only in the hieratic type of the personages and their sumptuous apparel, but also and still more undoubtedly in the mosaic borders by which they and the medallions beneath are framed. The tones are rich and soft as those of a Persian rug; the patterns and devices are clearly related to those in Byzantine ivories and enamels. Nor will the simile I have used seem inept when it is remembered that at this very time imitations of the Persian rugs brought home by the Crusaders were being deliberately manufactured in Paris. The enjoyment of colour is one of the finest of pleasures, but it was not merely to give pleasure that this glass was stained, and these figures drawn in lead. There is a reasoned aim, a definite symbolic purpose in all mediæval art, and not least in the art of stained glass.