Editing Arles (section)

===Roman aqueduct and mill===
[[File:Aqueduc Romain près de Fontvieille 2.JPG|thumb|Aqueduct of Arles at Barbegal]]
The [[Barbegal aqueduct and mill]] is a [[List of Roman watermills|Roman watermill]] complex located on the territory of the commune of [[Fontvieille, Bouches-du-Rhône|Fontvieille]], a few kilometres from Arles. The complex has been referred to as "the greatest known concentration of mechanical power in the [[ancient world]]".<ref>{{cite journal |first=Kevin |last=Greene |title=Technological Innovation and Economic Progress in the Ancient World: M.I. Finley Re-Considered |journal=The Economic History Review |series=New Series |volume=53 |issue=1 |year=2000 |pages=29–59 [p. 39] |doi=10.1111/1468-0289.00151 |hdl=10.1111/1468-0289.00151 |hdl-access=free }}</ref> The remains of the mill streams and buildings which housed the overshot [[water wheel]]s are still visible at the site, and it is by far the best-preserved of ancient mills. There are two aqueducts which join just north of the mill complex, and a sluice which enabled the operators to control the water supply to the complex. The mill consisted of 16 water wheels in two separate rows built into a steep hillside. There are substantial masonry remains of the water channels and foundations of the individual mills, together with a staircase rising up the hill upon which the mills are built. The mills apparently operated from the end of the 1st century until about the end of the 3rd century.<ref>{{cite web |url=http://www.patrimoine.ville-arles.fr/arles/ville.cfm?action=edifice_histoire&id=95 |title=Ville d'Histoire et de Patrimoine |publisher=Patrimoine.ville-arles.fr |access-date=2013-03-25 |url-status=dead |archive-url=https://web.archive.org/web/20131206194648/http://www.patrimoine.ville-arles.fr/arles/ville.cfm?action=edifice_histoire&id=95 |archive-date=2013-12-06 }}</ref> The capacity of the mills has been estimated at 4.5 tons of [[flour]] per day, sufficient to supply enough bread for 12,000 of the 30,000–40,000 inhabitants of Arelate at that time.<ref>{{cite web |url=http://www.etab.ac-caen.fr/lescourtils/provence/barbegal.htm |title=La meunerie de Barbegal |publisher=Etab.ac-caen.fr |access-date=2013-03-25 |archive-url=https://web.archive.org/web/20070117123744/http://www.etab.ac-caen.fr/lescourtils/provence/barbegal.htm |archive-date=2007-01-17 |url-status=dead }}</ref> A similar mill complex existed also on the [[Janiculum]] in [[Rome]]. Examination of the [[mill leat]] still just visible on one side of the hill shows a substantial accretion of lime in the channel, tending to confirm its long working life.

It is thought that the wheels were overshot water wheels with the outflow from the top driving the next one down and so on, to the base of the hill. Vertical water mills were well known to the Romans, being described by [[Vitruvius]] in his ''[[De Architectura]]'' of 25 BC, and mentioned by [[Pliny the Elder]] in his [[Naturalis Historia|Natural History]] of 77 AD. There are also later references to floating water mills from [[Byzantium]] and to [[sawmill]]s on the river [[Moselle]] by the poet [[Ausonius]]. The use of multiple stacked sequences of [[reverse overshot water wheel]]s was widespread in Roman mines.