362. I am about to examine, according to the preceding views, the coloured glass windows which concur so powerfully with architecture, in giving to vast gothic churches that harmony which we cannot fail to recognise whenever we enter them. These structures rank with those works of art which are most impressive by their size, the subordination of their various parts, and by their complete fitness for the purposes to which they are applied. The stained glass of gothic churches has always a most appropriate effect, intercepting the white light, which, by giving too vivid a glare, is less conducive to meditation than the coloured light which this glass transmits. We shall find its splendid effect to arise, not only from the contrast of colours, but also from the contrast of its transparency with the opacity of the surrounding walls, and of the lead which binds its parts together. The impression produced on the eye by this twofold cause becomes more vivid the more frequently it is repeated and the longer it is sustained, when yellow, blue, violet, orange, red, and green stained glass appears like most precious jewels. 363. The upright windows usually represent, within a border or a ground analogous to the rose windows, the figure of a saint in harmony with those which stand in relief about the portals of the edifice; and to be fully appreciated they must be judged of as _parts of a whole_, and not as a Greek statue which is intended to be seen isolated on all sides. The glass is of two kinds, the one painted on its surface by pigments afterwards vitrified (glass painting); the other, melted with the material that colours it (glass staining); the first is generally used in the composition of the nude parts of the human figure, and the second in that of the drapery. All the pieces of glass are united by strips of lead. What has struck me as being most effective in windows with human figures, is the exact observance of the relations of size of the figures and of the intensity of the light which renders them visible, with the distance at which the spectator is placed; a distance at which the strips of lead surrounding each piece of glass appear only as lines or as small black bands. 364. It is not necessary, for an effective whole, that the _painted glass_, when viewed closely, should exhibit fine hatchings, careful stippling, or blended tints; for, with the coloured stained glass for draperies, they should compose a system which compares with painting in flat tints, and certainly we cannot doubt that a painting on glass, executed entirely according to the system of _chiaro-scuro_, not to speak of the cost of its execution, will have the disadvantage of the finish in its details entirely disappearing at the distance at which it must be viewed as a whole.