Maria Liberatrice and S. Teodoro are situated, which formed the southern side of the lake, and the Forum Romanum the northern side. The Aqua Juturnæ, marked 1056 in Nolli’s Map, is the stream that gushes out in great volume from the rock at the foot of the Palatine in the Lupercal of Augustus, which is now in a very ruinous state, the cave being used as a mill-head to a modern mill, between that point and the Cloaca Maxima. This cave is close to the Carceres of the Circus Maximus. The authority for the name of this stream is doubtful; it is now usually called Aqua Argentina, and falls into the Cloaca Maxima, near the church of S. Giorgio in Velabro and the arch erected by the silver-smiths in honour of Septimius Severus. [6] The Augustan is a name applied also to a branch of the Marcian close to its source, as well as to one supplementary to the Appian within the city. [7] Frontinus, c. 5. [8] Ibid. [9] “Jungitur ei ad Spem [Specum] veterem in confinio hortorum Torquatianorum et Pallantianorum ramus Augustæ, ab Augusto in supplementum ejus additus, ... loco nomen respondenti Gemellarum.” (Ibid.) [10] “Incipit distribui [Aqua] Appia imo Publicii clivo ad portam Trigeminam.” (Ibid.) And again: “Rivus Appiæ, sub Cœlio monte et Aventino actus, emergit, ut diximus, infra clivum Publicii.” (Ibid., c. 22.) The cave reservoir which formed the mouth of this stream, where it was distributed, has been found near the Marmorata, or marble-wharf. The Porta Trigemina was between that and the Salaria, or salt-wharf. Both of the wharves are still in use. Some good antiquaries consider that the Porta Trigemina consisted of three double gates, at intervals along the narrow strip of ground between the Aventine and the Tiber, and that the one of which remains have been found near the Sublician bridge was the middle one of the three: if so, this cave would be literally _in_ the Porta Trigemina. In any case, it must have been close to it. [11] That is, in the reservoir, or _castellum aquæ_, through which the conduit or _specus_ passed. This reservoir exists, or rather considerable remains of it, just within the Porta Maggiore, between that and the church of S. Croce, and just outside the _agger_ of the Sessorium, on which the road from S. Croce to this gate now runs. [12] “... Cujus aquæ ad caput inveniri mensura non potuit, quoniam ex duobus rivis constat. Ad Gemellos tamen, qui locus est infra Spem (_Specum_) veterem, ubi jungitur cum ramo Augustæ, inveni altitudinem aquæ pedum quinque, latitudinem pedis unius, dodrantis: fiunt areæ pedes octo, dodrans: ... quas esse ex eo adparet quod in plerisque urbis partibus perdita aqua observatur, id est quæ ex ea manat, sed et quasdam fistulas intra urbem illicitas deprehendimus, extra urbem autem propter pressuram libræ, quam vidi infra terram ad caput pedibus quinquaginta, nullam accipit injuriam.” (Frontinus, c. 65.)