IX. THE ANIO NOVUS. “The Anio Novus, at the forty-second milestone, on the _Via Sublacensis_, at _Simbruinum_[126], is taken out of the river, which, since it has about it cultivated land in a rich territory, and so very loose banks, flows muddy and turbid even when uninfluenced by violent rains; and therefore at the very entrance of the channel is placed a cistern for the mud (_piscina limaria_), so that the water on its way from the river to the _specus_ should settle and become clear. From this cause also when heavy showers come down, the water flows into the city in a muddy state. “There is joined to it the _Rivus Herculaneus_[127] which rises on the same road at the thirty-eighth milestone, in the same neighbourhood as the springs of the Claudian, on the other side of the river and the road. This is very pure by nature, but when mixed it loses the advantage of its freshness. “The channel of the Anio Novus is in length 58 miles, 700 paces. Out of this 49 miles, 300 paces is by a subterranean channel;—on work above ground 9 miles, 400 paces; out of this on substructure or on arched work in several places in the upper part 2 miles, 300 paces, and nearer the city, from the seventh milestone, on a substructure of channels 609 paces, on arched work 6 miles, 491 paces. These are the highest arches, elevated in some places 109 feet[128]. “Nor was it enough for our Emperor [Nerva] to have restored an abundant and pleasant supply of water in the other aqueducts; he thought he saw his way to getting rid of the bad qualities _even of the Anio Novus_, he therefore ordered the _source to be changed from the river_, which was now left alone, and taken instead _from the lock in which_ the water was most pure, and which _is situated above Nero’s villa on the lake_ (_super villam Neronianam Sublaquensem_[129]);” i.e. at Subiaco, now a medieval castle and a modern town. “But the water of the Anio Novus often spoilt the rest, for since it was the highest as to level, and held the first rank as to abundance, it was most often made use of to help the others when they failed. The stupidity, indeed, of the Aquarii was such that they introduced this water into the channels of several others where there was no need, and spoilt water which was flowing in abundance without it. This was the case especially as regards the Claudia, which came all the way for many miles in its own channel perfectly pure, but when it reached Rome, and was mixed with the Anio, lost all its purity. And thus it happened that most of the streams were not in fact helped at all by the addition of the extra water, through the want of care on the part of those who distributed it[130].” THE NERONIAN ARCHES.