The total impression the aqueducts give is one of efficiency, organization, and heedlessness of expense, under the Republic as well as under the Empire. They were built with the spoils of wars or the tribute of provinces. The Marcia, built with the proceeds of the loot of Carthage and Corinth, cost 180,000,000 sesterces, or $9,000,000 uninflated. The Tepula, of 125 B.C., was perhaps built with the profits from the organization of the new province of Asia. From Agrippa’s time onward, and especially in Frontinus’ administration, the aqueduct service employed a large bureaucracy; overseers, reservoir-superintendents, inspectors, stonemasons, plasterers (the stone-built channels were lined with two or three coats of hydraulic cement), and unskilled laborers. Maintenance was a constant problem. Arches needed propping, filling in, or brick facing; piers needed to be buttressed or brick-encased. There was no attempt to produce high pressure: lead pipes would not have stood it, and for public use it was not necessary. There was no attempt to make the aqueducts financially self-supporting: their original building was one of the benefactions expected of successful commanders. Since these nabobs expected a quid pro quo in the gift of power, the aqueducts are a symbol, under the Republic of irresponsible oligarchy, and under the Empire of increasingly irresponsible autocracy, though “good” Emperors like Augustus, Claudius, Trajan, and Hadrian had a hand in them. In Augustus’ reign were built the Julia, the Virgo, and the Alsietina. Trajan built a northern line from Lago di Bracciano to Rome’s Trastevere quarter on the right bank of the Tiber: part of its course runs under the courtyard of the American Academy. Hadrian executed major repairs, datable by the omnipresent brick stamps. But even good Emperors knew no way of financing such public works except bleeding the taxpayer. In municipalities, private capital was absorbed in such public enterprise, with no return in income or local employment commensurate with the capital involved. So one major conclusion from Ashby’s and Miss Van Deman’s work is that the Romans were better engineers than they were economists. Let the last word on aqueducts be Pliny the Elder’s: “If one takes careful account of the abundant supply of water for public purposes, for baths, pools, channels, houses, gardens, suburban villas; the length of the aqueducts’ courses—arches reared, mountains tunnelled, valleys crossed on the level—he will confess that there has never been a greater marvel in the whole world.”
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One of the latest pieces of Roman engineering, to a knowledge of which archaeology has recently contributed, is Aurelian’s Wall. It has been meticulously studied by a pupil of Ashby’s, I. A. Richmond, now Professor of Archaeology of the Roman Empire at Oxford. Two-thirds of it is still standing ([Fig. 12.10]), to the disgust of those interested in the unimpeded flow of Rome’s traffic, to the delight of those in love with Rome’s past. It was twelve miles long, twelve feet thick, sixty feet high; it had 381 towers, each with a latrine, and eighteen portcullised gates, nine of which survive ([Fig. 12.11]). Though the Renaissance humanist Poggio Bracciolini had examined the wall as early as 1431, and the Frenchman Nicholas Audebert had studied it scientifically in 1574, Richmond was still able to make important contributions. He emphasizes, for example, that one-sixth of the wall incorporated buildings: tombs, houses, park walls, aqueducts, cisterns, porticoes, an amphitheater, a fortress. The inference is that the wall had to be built with speed and economy, in the face of the threat of barbarians in north Italy and a depleted treasury. Strategic reasons, of course, dictated the protection of the aqueducts. The use of tombstones as latrine covers shows, says Richmond, that the wall builders “had their religious scruples under excellent control.” It was a sense of urgency and not solicitude for works of art that prompted them, when they built a garden wall at Porta San Lorenzo into the circuit, to leave the statues in their niches and pack them round with clay.
Fig. 12.10 Rome, Aurelian’s Wall, from south, near Porta Appia.
(H. Kähler, Rom und seine Welt, Pl. 252)
Aurelian’s Wall and Major Monuments
LEGEND
Roads and Gates
I Porta Pinciana—Via Salaria
II Porta Salaria
III Porta and Via Nomentana
IV Porta and Via Tiburtina
V Porta Praenestina (Maggiore): major aqueduct junction; Via Praenestina
VI Porta Asinaria—Via Tusculana
VII Porta and Via Latina
VIII Porta and Via Appia
IX Porta and Via Ostiensis
X Porta and Via Portuensis
XI Porta Aureliana (S. Pancrazio); Aquae Alsietina and Traiana; Via Aurelia
XII Porta and Via Flaminia
Monuments
1 Forum
2 Argentina Temples
3 Cloaca Maxima
4 Pompey’s Theater and Portico
5 Imperial Fora
6 Altar of Peace
7 Augustus’ Mausoleum
8 Subterranean Basilica
9 Golden House
10 Coliseum
11 Cancelleria Palace
12 Domitian’s Stadium
13 Temple of Venus and Rome
14 Pantheon
15 Hadrian’s Mausoleum
16 Baths of Caracalla
17 Baths of Diocletian
18 Cemetery under St. Peter’s
Fig. 12.11 Rome, Aurelian’s Wall, plan, with major Imperial monuments.