Nor was this the only novelty in the method of imparting colour to glass. They now began to enrich their palettes by coating one colour with another, thus getting a tint not before obtainable. For example, red on blue gave a rich purple, blue on yellow a fine green, &c. This was effected in a very simple manner. Suppose the glass-blower wanted a purple--he dipped his pipe into liquid blue glass, and started to blow his bubble. When it began to take shape he dipped the small bubble into liquid red glass and then finished his blowing. This last dipping of course coated the outside of the blue bubble with red, and when it was completely blown, cut and opened out, it produced a sheet which was red on one side and blue on the other. Held up to the light, the red and blue combined to produce purple. Nor did the glass-blower confine himself to combinations of two colours, for the writer knows of an instance in France showing six superimposed coats. The French call this "verre doublé" (or lined glass), a very descriptive name. In passing we may say that although this manner of colouring glass first reached prominence during the Decorated period, it was but an elaboration of the way the ruby or red glass had always been made, _i.e._, coated on to the colourless glass. We have said that the earlier canopies did not have pedestals below them. This lack was soon noted, and the need was felt for something to complete them below; the first expedient hit upon for this purpose was shields gay with heraldic tinctures. Not only were these decorative, but we shall learn at Tewkesbury and Gloucester how valuable they have proved to be in enabling those learned in heraldry definitely to date windows whose histories have long since been forgotten. It must not be overlooked that the architect had much to do with the development from the mosaic to the canopy style. He decided to change from the wide single windows that one sees at Salisbury, and to substitute for them groups of narrower lights separated only by slender stone mullions and all bound together at the top and tapered off by a pyramid of smaller openings called tracery lights. These latter will be particularly enjoyed by the glass-lover while studying this period, for the Decorated glazier was singularly happy in his treatment of these smaller panes--much more so, in fact, than his successor of the Perpendicular era, who was obliged to conform to the stiff little pill-boxes provided for him by the architect. The use of vines and leaves was of great assistance in this problem of treating small irregular openings; nor were these the only motives--at Wells there is a very happy use of busts filling small trefoils.