The wall, up to the springing of the dome, is beautifully decorated with rich architecture in marbles of varied colour, and it cannot be doubted that the cupola--the very soul of the design--was embellished in a manner fully proportioned to the beauty of its sustaining wall; indeed, it is thought to have been coated with gilded bronze.[62] When thus perfect, it must have formed an interior of surpassing beauty, lighted as it was solely through the central eye, and the light tempered by the linen veil stretched across its rich bronze cornice, which still remains round the opening, and retains vestiges of gilding. The Pantheon can scarcely be called a _daring_ effort of construction, because its vast solidity seems to defy all doubts as to its duration. It would be, however, absurd to suppose it to have been an _early_ effort; for it is, as I have already said, so artificial in its construction, as clearly to prove it to be the result of long-continued practice. The walls, which I have described as being 20 feet thick, are so only in theory, for practically they are hollowed into innumerable cells, some of them forming beautiful architectural recesses, and others merely constructional hollows. The dome itself is constructed in a manner evincing long-continued practice; for it differs _toto cælo_ from the normal mode of construction. It is shown differently by different authors; in fact, it has probably never been sufficiently exposed to obtain complete information as to its curiously complicated construction. As far, however, as I can ascertain, it seems to be in two thicknesses. The inner thickness consists of the framework of the coffers, which is of brick, and the filling-in of the coffers, which is of rubble or concrete. This would form the centering on which the outer shell was built, which is a curious tissue of arches, each rising from the crowns of those below it, and so disposed as to concentrate the pressure upon points in the wall which intervene between the cells. The spaces between these arches are filled in (so far as I can gather) with rubble or concrete. The whole was probably covered externally with plates of bronze or of marble. The antique Roman dome of the so-called Temple of Minerva Medica--named from the discovery of a statue of that deity among its ruins, but now supposed by some to have been, like the Pantheon itself, the great hall of some public baths--greatly resembles the Pantheon in its general idea, but differs in this essential particular, that its surrounding wall is not circular, but decagonal (Fig. 402).