The Cathedral offers to the student of glass a perfect model, not indeed of detail, for upon the path which leads to the perfection of detail the thirteenth-century glazier had still many steps to take, but of effects in decorative colouring. In the rose you have a confused effect of colour, in which there is not any too definite form to spoil the charm of the broken bits of colour upon the senses. The meaning is there, too, as we shall see, many meanings, simple and elaborate, direct and mystical. But it is in the lancet windows of the nave that the row of otherwise (let it be confessed) ungainly figures supplies us at once, by means of the drapery, cloaks and borders, with that mixture of colour and shade that makes colour beautiful, and with those broad masses of stain combined with absolute simplicity and severity of design which should be the ideal of the glazier. And they are not crowded with too much story. The lesson of the army of saints and martyrs which they represent is printed in large type, so that it may be easily read and understood from the distant level of the nave. Each light exhibits one enormous figure of a saint, with features strongly marked, clad in bright robes of blazing colour, set off by a border that is more sober in tone and opaque. The fire dies out of these broad patches of limpid blue and emerald green, of flaming red and saffron yellow, as they approach the deep, cool borders of brown and black, violet and grey, mingled with lower tones of red and green. You see, then, the object and the successful result of these bold designs of huge saints. The mediæval glaziers had considered the position which their glass was to occupy in the Cathedral. They did not merely design it with a view to its being effective in the studio. There is another point to be noted. Working, as they did, with small fragments of the precious glass as it came out of the melting-pot, and binding each fragment in lines of lead till the whole formed a pattern or drawing in a leaden framework, they were able to watch and test their work in its progress. Thus, watching and testing, they were able also to arrange for the proper mingling of the rays diffused on all sides by each piece of the mosaic. They did not aim so much at painting a good preliminary design upon paper as at producing a fine effect of colour in glass. When in succeeding centuries painters invaded the realms of glass they would appear to have ignored the obvious requirements of the new medium in which they were to work. Experimentally and intuitively the mediæval glazier, on the other hand, must have studied the whole question of radiation as it affected his task. And the result is, that for the most superb effects of stained glass we have to go, not to the pictures burnt on the large sheets of glass by famous painters, but to the designs of the thirteenth-century anonymous monkish craftsmen. In the matter of stained glass the latter had this advantage also in their favour.