Above Specus of Appian. Palmi. Feet.
Anio Novus 173.8 127
Claudian 163.2 119
Julian 145.1 106
Tepulan 138.7 101½
Marcian 128.7 92½
Anio Vetus 75.4½ 55½
Virgo 9.3 7
Appian — —
At a lower level than Specus of the Appian.
Alsietina in the Trastevere 37.6½ 27½

He gives as the total full range, i.e. from the specus of the Alsietina (the lowest), to that of the Anio Novus (the highest), as 211.2½ palmi, or 154½ English feet. The height of the Appian, he shews by his diagram to be about 24 English feet above the Quay of the Tiber. The points at which Piranesi obtained his measurements, and the mode employed, are not recorded. It seems hardly possible that the Appia is 55 ft. under the Anio Vetus in Rome.

[36] See ante. Frontinus, cap. 21.

[37] The passage, as it stands in the Codex Cassinensis, is, “Anio Vetus citra quartum miliarium infra novum qui a Via Latina in Lavicanam inter arcus trajicit, et ipse piscinam habet.” This piscina is visible at the third modern milestone on the Via d’Albano, and at the fourth on the Via Latina. The Codex Vaticanus is an inferior copy of the Codex Cassinensis; but the Codex Urbinas, now also in the Vatican Library, is distinct. No other MS. is of any authority.

[38] Remains of the tombs on the Via Latina are distinctly visible and rather prominent objects, close to the Torre Fiscale. The Marrana, or Almo, the small stream that received the surplus water of the aqueducts, also washes the foot of the tower.

[39] This castellum aquæ is exactly two miles from the Porta Maggiore, another proof that the entrance to Rome (though not to the City) was considered by Frontinus to have been at that gate. All the aqueducts on the eastern side of Rome are measured by him from this gate, and the inscriptions put over that gate as the entrance into Rome indicate the same thing. The level of this castellum above the sea is about 153 ft.; at the Porta Maggiore, where the Anio Vetus enters Rome, it is about 146 ft., allowing a descent of about 3 ft. 4 in. for the two miles, which is natural. The Via Appia Nova, in the part near Rome, was made out of the old Via Asinaria. Frontinus says that this branch “was conveyed to the Asinian gardens,” which were between the Lateran and the Sessorium, and to which the Porta Asinaria (or gate of the Asinii) was the entrance. Between that gate and the Amphitheatrum Castrense are remains of an ancient reservoir or castellum aquæ, cut in the rock at the foot of the wall and half underground, as was very usual with the Anio Vetus. The branch that goes along the Via Latina appears to have gone from the same reservoir, but to be distinct from the one mentioned by Frontinus, and to have been made after his time. This last branch seems to be the same as the Aqua Antoniniana of the Regionary Catalogue, having been made in the third century to supply the great Thermæ of the Antonines. In the Middle Ages, this was considered to have been a branch of the Aqua Marcia; but if this had been the case, there must have been some remains of the arcade for it across the valley.

[40] This branch is believed to have been called Aqua Antoniniana, as it conveyed water to supply the great Thermæ of the Antonines, called after Antoninus Caracalla. But it seems doubtful whether it may not be the Severiana, which conveyed water to the Thermæ of Septimius Severus. There appear to have been two aqueducts along this point of the Via Latina at different levels, and the higher one, passing over the Arch of Drusus, is said to have been a branch from the Marcia.

[41] Frontinus, c. 21. On the subject of the word Spes (?) or Specus (?), see the Appendix to this Chapter.

[42]

ANIo
IMP . CAESAR
divI . f . avgvsT . ex . sc
VII PCCXL