THE RESERVOIR OF NERO.
Suetonius tells us "he made a reservoir like unto a sea," which no doubt was afterwards used to supply the Colosseum with water for the naval combats. The quadrata of the Cœlian is artificially formed, and was evidently the great nymphæum connected with the Golden House. The water was brought from the Claudian Aqueduct at the Porta Maggiore upon arches, known as Nero's Arches, which ended near the Temple of Claudius, and these arches end in the gardens now supported by the walls forming the quadrata. The niches and hemicyclia on the east side, with their channels of supply behind, were evidently fountains, and the west side was probably similar in character, some of the specuses still existing. The front towards the Colosseum formed a grand cascade, the water falling into the reservoirs, the ruins of which we see in advance of the north wall of the quadrata, and at a lower level; from these it poured into the great stagnum or lake below, now occupied by the Colosseum. Signor Alberto Cassio found specuses all around the top, and a euripus or channel at the base; and stalactites and opus signinum can still be seen there.
Turning to the right we pass under some medieval arches—flying buttresses—to support the church. On the left are some remains of the house of Gregory; and, on the right, the wood of the Cœlian. This hill was the ancient Clivus Scauri. To the left the steps lead up to