248 On the Building Materials used hy the Roimans. 



may be seen near the Anio, at Cerveretta, five miles beyond the 

 Porta Maggiore, to the left of the Via Collatina. It is a volcanic 

 production, of a colour more or less red, and of no great solidity, 

 as it is easily decomposed by exposure to the atmosphere. The 

 foundations of the buildings on the Palatine Hill are of this 

 stone, and the Temple of Fortuna Virilis, and the aqueduct of 

 Claudius, are also built of it. In this case, they either rough- 

 cast the outer part of the wall, or cut it in sufficiently large 

 pieces to resist the action of the air; the first method is observed 

 in the above mentioned temple, and the other is found in the 

 aqueduct of Claudius. Tuffa was employed also in Rome and 

 its neighbourhood, for that sort of building, which, from its 

 form, was called reticulated. This commenced on the decline 

 of the Republic, and ceased about the time of Caracalla. The 

 vicinity of Naples abounds also with this stone, and indeed the 

 city is almost entirely built of it. The grotto of Posillipo passes 

 through a mountain of this sort, and the perforations in the 

 neighbourhood of Cumae, Raise, &c. which are supposed to have 

 been the abodes of the Cummelii mentioned by Homer, are dug 

 in the same volcanic matter. 



Lapis albanus, Peperino, also a volcanic production, derived 

 its name from Mount Albanus, and its quarries are seen at pre- 

 sent in the neighbourhood of Marino ; its greenish greyish 

 colour^ and the resemblance it bears to pounded pepper, has 

 given rise to the vulgar name of Peperino. This stone, as well 

 as that called Lapis Gabinus, resists the action of fire ; and, on 

 that account, Nero, according to Tacitus, issued a decree, after 

 the burning of Rome, that all the houses should be built of one 

 or other of these stones. The peperino is more solid than tuffa, 

 and is less influenced by atmospheric changes, though it also suf- 

 fers. The walls of Servius at Rome were built of it, as may be 

 still observed under the temple of Victory, on the declivity of 

 the Quirinal, where there are still some remains. It has also 

 been employed in the erection of the enclosure of the forum of 

 Nerva, the temple of Antoninus, and Faustina, &c. The Lapis 

 Gahinus very much resembles peperino, and is found at Gabii, 

 about twelve miles from Rome. Its colour is the same ; but it 

 is much harder and more porous ; the ancients employed it more 

 particularly for millstones. 



