Bk. IV. Ch. IV, BASILICAS. 321 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 masonryj destroying the stability of the vault. Still, some of these in Rome have resisted for fifteen centuries, after the removal of anyj covering they ever might have had, all the accidents of climate and decay, while thei-e 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 cajjable of resisting the destructive effects of exposure to the atmosphere still remains a prob- lem for modern architects to solve. Until this is accomplished we must regard roofs entirely of honest wood as preferable to the decep- tive stone ceilings which were such favorites in the Middle Ages. The provincial basilicas of the Roman Empire have nearly all perished, probably from their having been con- verted, first into churches, for which they were so admirably adapted, and then rebuilt to suit the exigencies and taste of subsequent ages. One ex- ample, however, still exists in Treves of sufticient completeness to give a good idea of what such structures were. As Avill be seen by the annexed plan, it consists of a great hall, 85 feet in width internally, and rather more than twice that dimen- sion in lengtli. The walls are about 100 feet in height and pierced with two rows of windows j but whether they were originally separated by a gallery or not is now by no means clear. At one end was the apse, rather more than a semi- circle of 60 ft. in diameter. The floor of the apse was raised considerably above that of the body of the building, and was no doubt adorned by a hemicycle of seats raised on steps, with a throne in the centre for the judge. The building has been used for so many purposes since the time of the Romans, and has been so much altered, that it is not easy now to speak with certainty of any of its minor arrangements. Its internal and external appearance, as it stood before the recent restoration, are well expressed in the annexed woodcuts ; and though ruined, it was the most complete exam])le of a Roman basilica to be found anywhere out of the capital. A building of this description has been found at Pompeii, which may be considered a fair example of a provincial basilica of the second class. Its plan is perfectly preserved, as shown in Woodcut No. 207. The most striking difference existing between it and those previously described is the square termination instead of the circular apse. It must, however, be vol.. I. — 21 Plan of the Basilica at Trfeves. Scale 100 ft. to 1 in.
