CH. III THE LAMP OF POWER 127

that much caution is necessary in the management of the glass. In the finest instances, the traceries are open lights, either in towers, as in this design of Giotto’s, or in external arcades like that of the Campo Santo at Pisa or the Doge’s Palace at Venice; and it is thus only that their full beauty is shown. In domestic buildings, or in windows of churches necessarily glazed, the glass was usually withdrawn entirely behind the traceries. Those of the Cathedral of Florence stand quite clear of it, casting their shadows in well-detached lines, so as in most lights to give the appearance of a double tracery. In those few instances in which the glass was set in the tracery itself, as in Or San Michele, the effect of the latter is half destroyed: perhaps the especial attention paid by Orcagna to his surface ornament, was connected with the intention of so glazing them. It is singular to see, in late architecture, the glass, which tormented the bolder architects, considered as a valuable means of making the lines of tracery more slender; as in the smallest intervals of the windows of Merton College, Oxford,¹ where the glass is advanced about two inches from the centre of the tracery bar, (that in the larger spaces being in the middle, as usual,) in order to prevent the depth of shadow from farther diminishing the apparent interval.* Much of the lightness of the effect of the traceries is owing to this seemingly unimportant arrangement. But, generally speaking, glass spoils all traceries; and it is much to be wished that it should be kept well within them, when it cannot be dispensed with, and that the most careful and

* Well noticed; and, I think, at that time by me only. I do not think this question of the advance or retreat of the glass has been touched even in M. Viollet-le-Duc’s long article on tracery, and I am more pertinacious now in showing what I have really seen and said, because it has all been so useless. Had it been acted on, I need not have vindicated my guidance-now, I can only say-“I showed you the right way, though you would not walk in it.” See the following note. [1880.]

¹ [The windows are of the same date as the choir, transepts, and ante-chapel, about 1276, except the lower part of the east window. Ruskin made drawings and measurements of these windows during a visit to Oxford in July 1848. The point here made in the text is noted and illustrated at considerable length in his diary.]

[Version 0.04: March 2008]