His treatise is well worth examination, not only from an archæological point of view, but as suggesting also many curious enquiries as to the engineering abilities which the Romans possessed, compared with those exhibited at the present day. In elucidating, however, the architectural antiquities of the city of Rome, it will be necessary, as far as possible, to limit the extracts from his treatise De Aquæductibus, to those portions which refer either directly to existing remains, or which indirectly explain them, by pointing out the principle on which the several Roman aqueducts seem to have succeeded each other.
Frontinus tells us in his fourth chapter, that for 441 years after the building of the city, or until B.C. 312, the people were content with the water which they could draw from the Tiber, or from wells[4] or from springs, of some of which the memory was in his time still held sacred and honoured, for they were thought to afford health to the sick[5].
Passing to his own time, he says, “there now flow into the city:”—
| I. | Aqua Appia. |
| II. | Anio Vetus. |
| III. | Aqua Marcia. |
| IV. | ” Tepula. |
| V. | ” Julia. |
| VI. | Aqua Virgo. |
| VII. | ” Alsietina (which is also called Augusta[6]). |
| VIII. | ” Claudia. |
| IX. | Anio Novus. |
Frontinus describes the above nine aqueducts in order, giving details as to the source of the water in each, the quantity, and the distribution. Such extracts as are calculated to throw light upon the existing remains, are given in the course of the following remarks. Seven other Aqueducts were added after the time of Frontinus at different periods, of which an account will also be found in the second part of this Chapter.
I. The Aqua Appia (A.U.C. 441, B.C. 312).
“The Aqua Appia was brought into Rome by the censor Appius Claudius Crassus, afterwards called Cæcus (the blind), who also caused the Via Appia to be constructed from the Porta Capena to the city of Capua[7].”
“The Appian stream rises in the Lucullan fields on the Via Prænestina, between the seventh and eighth milestone, and about 780 paces (or about ¾ of a mile) off on the left-hand side. The channel from its source to the ‘Salinæ,’ which is a spot near the Porta Trigemina, measures 11 miles, 190 paces (about 300 yards) in length. For 11 miles, 130 paces, (about 200 yards,) the channel runs underground, and for 60 paces (about 100 yards) it is carried above ground on a substructure and arcade (in the part) nearest to the Porta Capena[8]. At the ‘Spes (Specus) Vetus,’ (the old specus or conduit,) on the confines of the Torquatian and Pallantian gardens, a branch called the Augustan was added to it by Augustus as supplementary, whence it received the name of ‘Gemelli[9]’....”