§ XV. One farther circumstance is deserving of especial note in Plate V., the greater depth of the voussoirs at the top of the arch. This has been above alluded to as a feature of good construction, Chap. XI., § III.; it is to be noted now as one still more valuable in decoration: for when we arrive at the deep succession of concentric archivolts, with which northern portals, and many of the associated windows, are headed, we immediately find a difficulty in reconciling the outer curve with the inner. If, as is sometimes the case, the width of the group of archivolts be twice or three times that of the inner aperture, the inner arch may be distinctly pointed, and the outer one, if drawn with concentric arcs, approximate very nearly to a round arch. This is actually the case in the later Gothic of Verona; the outer line of the archivolt having a hardly perceptible point, and every inner arch of course forming the point more distinctly, till the innermost becomes a lancet. By far the nobler method, however, is that of the pure early Italian Gothic; to make every outer arch a _magnified fac-simile_ of the innermost one, every arc including the same number of degrees, but degrees of a larger circle. The result is the condition represented in Plate V., often found in far bolder development; exquisitely springy and elastic in its expression, and entirely free from the heaviness and monotony of the deep northern archivolts. § XVI. We have not spoken of the intermediate form, _b_, of Fig. LXIX. (which its convenience for admission of light has rendered common in nearly all architectures), because it has no transitions peculiar to itself: in the north it sometimes shares the fate of the outer architrave, and is channelled into longitudinal mouldings; sometimes remains smooth and massy, as in military architecture, or in the simpler forms of domestic and ecclesiastical. In Italy it receives surface decoration like the architrave, but has, perhaps, something of peculiar expression in being placed between the tracery of the window within, and its shafts and tabernacle work without, as in the Duomo of Florence: in this position it is always kept smooth in surface, and inlaid (or painted) with delicate arabesques; while the tracery and the tabernacle work are richly sculptured. The example of its treatment by colored voussoirs, given in Plate XIX., may be useful to the reader as a kind of central expression of the aperture decoration of the pure Italian Gothic;--aperture decoration proper; applying no shaft work to the jambs, but leaving the bevelled opening unenriched; using on the outer archivolt the voussoirs and concentric architrave in reconcilement (the latter having, however, some connection with the Norman zigzag); and beneath them, the pure Italian two-pieced and mid-cusped arch, with rich cusp decoration. It is a Veronese arch, probably of the thirteenth century, and finished with extreme care; the red portions are all in