of arrangement of the second kind of mass; that which is flat, and of shadow only.
XVIII. We have noted above how the wall surface, composed of rich materials, and covered with costly work, in modes which we shall examine in the next Chapter, became a subject of peculiar interest to the Christian architects. Its broad flat lights could only be made valuable by points or masses of energetic shadow, which were obtained by the Romanesque architect by means of ranges of recessed arcade, in the management of which, however, though all the effect depends upon the shadow so obtained, the eye is still, as in classical architecture, caused to dwell upon the projecting columns, capitals, and wall, as in Plate VI. But with the enlargement of the window, which, in the Lombard and Romanesque churches, is usually little more than an arched slit, came the conception of the simpler mode of decoration, by penetrations which, seen from within, are forms of light, and, from without, are forms of shade. In Italian traceries the eye is exclusively fixed upon the dark forms of the penetrations, and the whole proportion and power of the design are caused to depend upon them. The intermediate spaces are, indeed, in the most perfect early examples, filled with elaborate ornament; but this ornament was so subdued as never to disturb the simplicity and force of the dark masses; and in many instances is entirely wanting. The composition of the whole depends on the proportioning and shaping of the darks; and it is impossible that any thing can be more exquisite than their placing in the head window of the Giotto campanile, Plate IX, or the Church of Or San Michele. So entirely does the effect depend upon them, that it is quite useless to draw Italian tracery in outline; if with any intention of rendering its effect, it is better to mark the black spots, and let the rest alone. Of course, when it is desired to obtain an accurate rendering of the design, its lines and mouldings are enough;
