[87] The reader must always remember that a cornice, in becoming a capital, must, if not originally bold and deep, have depth added to its profile, in order to reach the just proportion of the lower member of the shaft head; and that therefore the small Greek egg cornices are utterly incapable of becoming capitals till they have totally changed their form and depth. The Renaissance architects, who never obtained hold of a right principle but they made it worse than a wrong one by misapplication, caught the idea of turning the cornice into a capital, but did not comprehend the necessity of the accompanying change of depth. Hence we have pilaster heads formed of small egg cornices, and that meanest of all mean heads of shafts, the coarse Roman Doric profile chopped into a small egg and arrow moulding, both which may be seen disfiguring half the buildings in London. [88] I have taken these dates roughly from Selvatico; their absolute accuracy to within a year or two, is here of no importance. [89] Chap. I. § XIX., Appendix 7: and Chap. VI. § V. [90] Chap. I., § XIX. CHAPTER XXVIII. THE ARCHIVOLT AND APERTURE. [Illustration: Plate XIX. ARCHIVOLT DECORATION. AT VERONA.] § I. If the windows and doors of some of our best northern Gothic buildings were built up, and the ornament of their archivolts concealed, there would often remain little but masses of dead wall and unsightly buttress; the whole vitality of the building consisting in the graceful proportions or rich mouldings of its apertures. It is not so in the south, where, frequently, the aperture is a mere dark spot on the variegated wall; but there the column, with its horizontal or curved architrave, assumes an importance of another kind, equally dependent upon the methods of lintel and archivolt decoration. These, though in their richness of minor variety they defy all exemplification, may be very broadly generalized. Of the mere lintel, indeed, there is no specific decoration, nor can be; it has no organism to direct its ornament, and therefore may receive any kind and degree of ornament, according to its position. In a Greek temple, it has meagre horizontal lines; in a Romanesque church, it becomes a row of upright niches, with an apostle in each; and may become anything else at the architect's will. But the arch head has a natural organism, which separates its ornament into distinct families, broadly definable.