“Alexandria is almost wholly undermined with water-courses, and has a specus extending to the Nile, by which water is conveyed into private houses[65].”
III. The Aqua Marcia (B.C. 145).
“127 years afterwards, that is, from the building of Rome 608 years, when Servius Sulpicius Galba and Aurelius Cotta were consuls, as the aqueducts or conduits (ductus) of the Appian and Anio were much decayed by age, (and also intercepted fraudulently for private purposes,) the business of repairing and reclaiming the said aqueducts was entrusted by the senate to Marcius, who was then acting as Prætor. And because the increase of the population of the city seemed to demand a more ample supply of water, instructions were given to him by the senate that he should carefully examine how far there were other streams which he might be able to bring into the city[66].
“He therefore restored the two old conduits, and introduced a third, which he caused to be erected with ‘squared stones,’ and larger aqueducts, and carried through them the water which he had obtained for the public service[67]. Hence it received the name of the ‘Marcian’ from himself, as the author of it.
“The Aqua Marcia has its origin on the Via Valeria at the thirty-sixth milestone, three miles off in the diverticulum (or cross-road), on the right-hand to those going from Rome. On the road to Sublacum, now called Subiaco (Via Sublacensis) also (which was paved for the first time under the Emperor Nero), at the thirty-eighth milestone, for the space of two hundred paces on the left-hand side the water lies like a pond, bubbling up in innumerable springs from beneath the stony hollows, and is very green in colour.
“The length of the course from its head to the city is 61 miles, 710 paces;—by an underground channel 54 miles, 247½ paces, on structure above ground 7 miles, 463 paces. Out of this, in many parts away from the city, in the upper part of the valleys, it is carried on arched substructure for 473 paces; nearer the city, from the seventh milestone, on a substructure for 528 paces. In the rest of the work it is carried on an arcade for 6 miles, 472 paces[68].”
“The Marcian ranks fifth in height, and is at its head even in level with the Claudian[69].”
“In the year of the building of the city, 719 (i.e. B.C. 44), Agrippa repaired the three aqueducts—the Appian, the Anio Vetus, and Marcian—and took care to supply the city with many fountains[70].”
“[Temp. Nervæ, (A.D. 96)] the Marcian having been enlarged was carried across from the Cœlian [i.e. its specus] to the Aventine[71].”