Before crossing the threshold into the two next periods (the Decorated and Perpendicular), it is worth pausing to notice that although architecture generally tends to elaborate as time goes on, the opposite was true in England during the two centuries of which we are about to speak. In fact, the work of the earlier of these two epochs obviously deserves the title of "Decorated" and the later does not. Its glass, too, is much more florid than its successor, and is far more ambitiously ornamental. It bears many bits of leafy foliage, twining vine tendrils, &c., all drawn as true to life as possible. Later these bits of flora are rarely used, and then only in a conventional and, therefore, less decorative form. In our introduction we have stated that in England, the arrival of the fourteenth century does not show the abrupt difference found in France between the light-obscuring mosaic glass of the thirteenth century and the fainter tints of the fourteenth, permitting the brighter interior then demanded. The explanation seems to be that the English, having been early forced by cloudy skies to use light-admitting grisaille (either alone, or combined with their early medallions) already enjoyed the proper illumination which, at the beginning of the fourteenth century, was so lacking in France as to bring about a cry for light at any cost. In place of the early fourteenth century glare that strikes one at Sées, Evreux, and in St. Ouen at Rouen, we have rich strong colour in their contemporaries at Tewkesbury, Wells and Bristol. Occasionally grisaille will be found pleasantly combined with small coloured scenes, as at Dorchester and in Merton Chapel, Oxford, but even then it seems much like a local survival of the thirteenth century tradition. So much for the difference between the English Decorated and the French fourteenth century windows. Now let us briefly consider what it was that succeeded to the mosaic medallion style seen at Canterbury, Lincoln, &c., and also what causes must have been at work to produce the change. About the end of the thirteenth century there chanced to be discovered a method of producing yellow which obviated the necessity of cutting out a piece of glass of that tint and laboriously leading it into the picture where needed, as was still obligatory if they wanted blue or red, &c. Some lucky glazier stumbled on the fact that if chloride of silver be put on a sheet of glass it would, when exposed to the fire, produce a handsome golden stain, and that only at the points to which it was applied. Many stories are related to explain this discovery, but as they are all more pleasing than convincing, it seems best to credit Dame Fortune with this valuable assistant to the glazier. It is obvious that this facility in staining a touch of yellow just at the point desired by the artist was eagerly seized upon. He at once made use of it to decorate the robes of great personages, or to brighten the hair of women and angels, as well