§ 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 brick, delicately cast: and the most remarkable feature of the whole is the small piece of brick inlaid on the angle of each stone voussoir, with a most just feeling, which every artist will at once understand, that the color ought not to be let go all at once.
§ XVII. We have traced the various conditions of treatment in the archivolt alone; but, except in what has been said of the peculiar expression of the voussoirs, we might throughout have spoken in the same terms of the jamb. Even a parallel to the expression of the voussoir may be found in the Lombardic and Norman divisions of the shafts, by zigzags and other transverse ornamentation, which in the end are all swept away by the canaliculated mouldings. Then, in the recesses of these and of the archivolts alike, the niche and statue decoration develops itself; and the vaulted and cavernous apertures are covered with incrustations of fretwork, and with every various application of foliage to their fantastic mouldings.
§ XVIII. I have kept the inquiry into the proper ornament of the archivolt wholly free from all confusion with the questions of beauty in tracery; for, in fact, all tracery is a mere multiplication and entanglement of small archivolts, and its cusp ornament is a minor condition of that proper to the spandril. It does not reach its completely defined form until the jamb and archivolt have been divided into longitudinal mouldings; and then the tracery is formed by the innermost group of the shafts or fillets, bent into whatever forms or foliations the designer may choose; but this with a delicacy of adaptation which I rather choose to illustrate by particular examples, of which we shall meet with many in the course of our inquiry, than to delay the reader by specifying here. As for the conditions of beauty in the disposition of the tracery bars, I see no hope of dealing with the subject fairly but by devoting, if I can find time, a separate essay to it—which, in itself, need not be long, but would involve, before it could be completed, the examination of the whole mass of materials lately collected by the indefatigable industry of the English architects who have devoted their special attention to this subject, and which are of the highest value as illustrating the chronological succession or mechanical structure of tracery, but which, in most cases, touch on their æsthetic merits incidentally only. Of works of this kind, by far the best I have met with is Mr. Edmund Sharpe’s, on Decorated Windows, which seems to me, as far as a cursory glance can enable me to judge, to exhaust the subject as respects English Gothic; and which may be recommended to the readers who are interested in the subject, as containing a clear and masterly enunciation of the general principles by which the design of tracery has been regulated, from its first development to its final degradation.
[91] The architrave is properly the horizontal piece of stone laid across the tops of the pillars in Greek buildings, and commonly marked with horizontal lines, obtained by slight projections of its surface, while it is protected above in the richer orders, by a small cornice.