Moreover, in the sandpits the roof is arched, and the vault of the arch springs from the very ground; whereas in the catacombs the walls of the galleries are made strictly perpendicular, in order that horizontal shelves, capable of supporting the bodies of the dead, might be safely cut in them, and the tiles that shut them in might have adequate support. In a word, the two kinds of excavation could hardly be mistaken for one another. A catacomb could only be made to look like a sandpit or quarry by first destroying all the graves, widening the paths, and rounding their angles; in a word, by destroying every characteristic of a catacomb; and a sandpit could be turned into a cemetery resembling the Catacombs, only by setting up such a quantity of masonry as must needs remain to tell its own tale. There are actual examples of this metamorphose to be found in three or four places of the Catacombs; and here is the representation of one of them, from the Catacomb of St. Hermes, on the Via Salara. What an amount of labour and expense was necessary to effect the change, and, after all, with a result how clumsy and unsatisfactory as compared with those places which were excavated directly and primarily for the purpose of burial!—so unsatisfactory, indeed, that presently the Christians left off prosecuting the work even here where they had begun it. Though immense spaces of the sandpit still remained unoccupied, they chose rather to excavate after their own fashion in the virgin rock below. We may conclude, then, without a shadow of doubt, that those excavations which we call the Roman Catacombs were made solely for the sake of burying the dead. [Illustration: _Sections of Gallery in St. Hermes._] But by whom? and to bury what dead? We answer, and again without hesitation—By Christians, and only to bury Christians. And if it is asked on what authority this statement is made, we might point to the thousands of Christian inscriptions that have been found in them, and to the utter absence of evidence in favour of any other account of them. Our readers, however, would probably insist that it was impossible for the early Christians, a small and persecuted body, going about stealthily and in disguise, as it were, among the Pagan multitude, to have executed so vast a work.