Note 145 — Chapter IV · PART I. THE AQUEDUCTS. (continued 2)

The large square part of the Cœlian Hill, with scarped cliffs round three sides of it and part of the fourth, which had probably been originally the arx or citadel of the Cœlian when that was a separate fortress, and on which Claudius erected some great public building with a temple, is marked on the modern maps of Rome as a castellum aquæ: this is an exaggeration. A specus runs along the western side opposite to the Palatine in the wall, and goes straight towards the Colosseum, and there are remains of a piscina of the first century at the north-west corner of the Claudium, near the Colosseum, and the Meta Sudans; but this is at a low level, and does not agree with there being a large reservoir under the whole of that space.