§ XI. (2.) The Tympanum. It was noted that, in Gothic architecture, this is for the most part a detached slab of stone, having no constructional relation to the rest of the building. The plan of its sculpture is therefore quite arbitrary; and, as it is generally in a conspicuous position, near the eye, and above the entrance, it is almost always charged with a series of rich figure sculptures, solemn in feeling and consecutive in subject. It occupies in Christian sacred edifices very nearly the position of the pediment in Greek sculpture. This latter is itself a kind of tympanum, and charged with sculpture in the same manner. § XII. (3.) The Gable. The same principles apply to it which have been noted respecting the spandril, with one more of some importance. The chief difficulty in treating a gable lies in the excessive sharpness of its upper point. It may, indeed, on its outside apex, receive a finial; but the meeting of the inside lines of its terminal mouldings is necessarily both harsh and conspicuous, unless artificially concealed. The most beautiful victory I have ever seen obtained over this difficulty was by placing a sharp shield, its point, as usual, downwards, at the apex of the gable, which exactly reversed the offensive lines, yet without actually breaking them; the gable being completed behind the shield. The same thing is done in the Northern and Southern Gothic: in the porches of Abbeville and the tombs of Verona. § XIII. I believe there is little else to be noted of general laws of ornament respecting the wall veil. We have next to consider its concentration in the shaft. Now the principal beauty of a shaft is its perfect proportion to its work,--its exact expression of necessary strength. If this has been truly attained, it will hardly need, in some cases hardly bear, more decoration than is given to it by its own rounding and taper curvatures; for, if we cut ornaments in intaglio on its surface, we weaken it; if we leave them in relief, we overcharge it, and the sweep of the line from its base to its summit, though deduced in Chapter VIII., from necessities of construction, is already one of gradated curvature, and of high decorative value.