the _Aqua Tepula_, in which it was merged as far as the reservoir (_piscina_) on the _Via Latina_, seven miles from Rome. From this reservoir the water was carried along two distinct channels, on the same substructions; the lower channel being called the _Aqua Tepula_, and the upper the _Aqua Julia_; and this double aqueduct again was united with the _Aqua Marcia_, over the watercourse of which the other two were carried.--6. The _Aqua Virgo_, built by Agrippa, to supply his baths. From a source in a marshy spot by the 8th milestone on the _Via Collatina_, it was conducted by a very circuitous route.--7. The _Aqua Alsietina_ (sometimes called also _Aqua Augusta_), on the other side of the Tiber, was constructed by Augustus from the _Lacus Alsietinus_ (_Lago di Martignano_), which lay 6500 _passus_ to the right of the 14th milestone on the _Via Claudia_.--8, 9. The two most magnificent aqueducts were the _Aqua Claudia_ and the _Anio Novus_ (or _Aqua Aniena Nova_), both commenced by Caligula in A.D. 36, and finished by Claudius in A.D. 50. The water of the _Aqua Claudia_ was derived from two copious and excellent springs, near the 38th milestone on the _Via Sublacensis_. Its length was nearly 46½ miles. The _Anio Novus_ began at the 42nd milestone. It was the longest and the highest of all the aqueducts, its length being nearly 59 miles, and some of its arches 109 feet high. In the neighbourhood of the city these two aqueducts were united, forming two channels on the same arches, the _Claudia_ below and the _Anio Novus_ above. These nine aqueducts were all that existed in the time of Frontinus, who was the _curator_ of the aqueducts in the reigns of Nerva and Trajan. There was also another aqueduct, not reckoned with the nine, because its waters were no longer brought all the way to Rome, viz.: 10. The _Aqua Crabra_.--The following were of later construction. 11. The _Aqua Trajana_, brought by Trajan from the _Lacus Sabatinus_ (now _Bracciano_).--12. The _Aqua Alexandrina_, constructed by Alexander Severus; its source was in the lands of Tusculum, about 14 miles from Rome.--13. The _Aqua Septimiana_, built by Septimius Severus, was perhaps only a branch of the _Aqua Julia_.--14. The _Aqua Algentia_ had its source at _M. Algidus_ by the _Via Tusculana_. Its builder is unknown.--Great pains were taken by successive emperors to preserve and repair the aqueducts. From the Gothic wars downwards, they have for the most part shared the fate of the other great Roman works of architecture; their situation and purpose rendering them peculiarly exposed to injury in war; but still their remains form the most striking features of the Campagna, over which their lines of ruined arches, clothed with ivy and the wild fig-tree, radiate in various directions. [Illustration: Triple Aqueduct.]