202. Longitudinal Section of Basilica of Maxentius. Scale 100 ft. to 1 in.
203. Transverse Section of Basilica of Maxentius. Scale 100 ft. to 1 in.
The basilica of Maxentius, which was probably not entirely finished till the reign of Constantine, was rather broader than that of Trajan, being 195 ft. between the walls, but it was 100 ft. less in length. The central aisle was very nearly of the same width, being 83 ft. between the walls, and 120 ft. in height. There was, however, a vast difference in the construction of the two; so much so, that we are startled to see how rapid the progress had been during the interval, of less than two centuries, that had elapsed between the construction of the two basilicas.
204. Pillar of Maxentian Basilica. (From an old print quoted by Letarouilly.)
In this building no pillars were used with the exception of eight great columns in front of the piers, employed merely as ornaments, or as vaulting shafts were in Gothic cathedrals, to support in appearance, though not in construction, the springing of the vaults.[[176]] The side-aisles were roofed by three great arches, each 74 ft. in span, and the centre by an immense intersecting vault in three compartments. The form of these will be understood from the annexed sections (Woodcuts Nos. [202] and [203]), one taken longitudinally, the other across the building. As will be seen from them, all the thrusts are collected to a point and a buttress placed there to receive them: indeed almost all the peculiarities afterwards found in Gothic vaults are here employed on a far grander and more gigantic scale than the Gothic architects ever attempted; but at the same time it must be allowed that the latter, with smaller dimensions, often contrived by a more artistic treatment of their materials to obtain as grand an effect and far more actual beauty than ever were attained in the great transitional halls of the Romans. The largeness of the parts of the Roman buildings was indeed their principal defect, as in consequence of this they must all have appeared smaller than they really were, whereas in all Gothic cathedrals the repetition and smallness of the component parts has the effect of magnifying their real dimensions.
The roofs of these halls had one peculiarity which it would have been well if the mediæval architects had copied, inasmuch as they were all, or at least might have been, honestly used as roofs without any necessity for their being covered with others of wood, as all Gothic vaults unfortunately were. It is true this is perhaps one of the causes of their destruction, for, being only overlaid with cement, the rain wore away the surface, as must inevitably be the case with any composition of the sort exposed horizontally to the weather, and that being gone, the moisture soon penetrated through the crevices of the masonry, destroying the stability of the vault. Still, some of these in Rome have resisted for fifteen centuries, after the removal of any covering they ever might have had, all the accidents of climate and decay, while there is not a Gothic vault of half their dimensions that would stand for a century after the removal of its wooden protection. The construction of a vault capable of resisting the destructive effects of exposure to the atmosphere still remains a problem for modern architects to solve. Until this is accomplished we must regard roofs entirely of honest wood as preferable to the deceptive stone ceilings which were such favourites in the Middle Ages.
205. Plan of the Basilica at Trèves. Scale 100 ft. to 1 in.