Editing Water wheel (section)

==== Greco-Roman world ====
{{See also|List of ancient watermills}}

The technological breakthrough occurred in the technologically developed [[Hellenistic period]] between the 3rd and 1st century BC.<ref>{{harvnb|Wikander|2000|p=395}}; {{harvnb|Oleson|2000|p=229}}{{blockquote|It is no surprise that all the water-lifting devices that depend on subdivided wheels or cylinders originate in the sophisticated, scientifically advanced Hellenistic period, ...}}</ref> A poem by [[Antipater of Thessalonica]] praised the water wheel for freeing women from the exhausting labor of milling and grinding.<ref>{{Cite book |last1=Jahren |first1=Per |url=https://books.google.com/books?id=7teSDQAAQBAJ |title=How Water Influences Our Lives |last2=Sui |first2=Tongbo |date=2016-11-22 |publisher=Springer |isbn=978-981-10-1938-8 |language=en}}</ref><ref>{{Cite web |title=Antipater of Thessalonica: Epigrams - translation |url=https://www.attalus.org/poetry/antipater2.html |access-date=2024-09-12 |website=www.attalus.org}}</ref>

===== Water-lifting =====
[[File:WaterwheelsSp.jpg|thumb|Sequence of wheels found in [[Riotinto-Nerva_mining_basin#From_Antiquity_to_the_Middle_Ages|Rio Tinto mines]]]]

The compartmented water wheel comes in two basic forms, the wheel with compartmented body ([[Latin]] ''tympanum'') and the wheel with compartmented rim or a rim with separate, attached containers.<ref name="Oleson 2000, 229"/> The wheels could be either turned by men treading on its outside or by animals by means of a [[sakia]] gear. While the tympanum had a large discharge capacity, it could lift the water only to less than the height of its own radius and required a large torque for rotating.<ref name="Oleson 2000, 230">{{harvnb|Oleson|2000|p=230}}</ref> These constructional deficiencies were overcome by the wheel with a compartmented rim which was a less heavy design with a higher lift.<ref>{{harvnb|Oleson|2000|pp=231f.}}</ref>

The earliest literary reference to a water-driven, compartmented wheel appears in the technical treatise ''Pneumatica'' (chap. 61) of the Greek engineer [[Philo of Byzantium]] ({{Circa|280|220 BC}}).<ref>{{harvnb|Oleson|2000|p=233}}</ref> In his ''Parasceuastica'' (91.43−44), Philo advises the use of such wheels for submerging siege mines as a defensive measure against enemy sapping.<ref name="Oleson 2000, 234">{{harvnb|Oleson|2000|pp=234}}</ref> Compartmented wheels appear to have been the means of choice for draining [[dry dock]]s in [[Alexandria]] under the reign of [[Ptolemy IV]] (221−205 BC).<ref name="Oleson 2000, 234"/> Several Greek [[papyri]] of the 3rd to 2nd century BC mention the use of these wheels, but do not give further details.<ref name="Oleson 2000, 234"/> The non-existence of the device in the [[Ancient Near East]] before [[Wars of Alexander the Great|Alexander's conquest]] can be deduced from its pronounced absence from the otherwise rich oriental iconography on irrigation practices.<ref>{{harvnb|Oleson|2000|pp=235}}: {{blockquote|The sudden appearance of literary and archaological evidence for the compartmented wheel in the third century B.C. stand in marked contrast to the complete absence of earlier testimony, suggesting that the device was invented not long before.}}</ref>{{failed verification|reason=could not find mention of Alexander or conquests|date=January 2022}}<ref>An isolated passage in the Hebrew [[Deuteronomy]] (11.10−11) about Egypt as a country ''where you sowed your seed and watered it with your feet'' is interpreted as an metaphor referring to the digging of irrigation channels rather than treading a waterwheel ({{harvnb|Oleson|2000|pp=234}}).</ref><ref>As for a Mesopotamian connection: {{harvnb|Schioler|1973|p=165−167}}: {{blockquote|References to water-wheels in ancient [[Mesopotamia]], found in handbooks and popular accounts, are for the most part based on the false assumption that the [[Akkadian language|Akkadian]] equivalent of the logogram GIS.APIN was ''nartabu'' and denotes an instrument for watering ("instrument for making moist").}}{{blockquote|As a result of his investigations, Laessoe writes as follows on the question of the saqiya: "I consider it unlikely that any reference to the saqiya will appear in ancient Mesopotamian sources." In his opinion, we should turn our attention to Alexandria, "where it seems plausible to assume that the saqiya was invented."}}</ref><ref>{{citation|title=Water architecture in the lands of Syria: the water-wheels|author=Adriana de Miranda|publisher=L'Erma di Bretschneider|year=2007|isbn=978-8882654337|pages=48f}} concludes that the Akkadian passages "are counched in terms too general too allow any conclusion as to the excat structure" of the irrigation apparatus, and states that "the latest official [[Chicago Assyrian Dictionary]] reports meanings not related to types of irrigation system".</ref> Unlike other water-lifting devices and pumps of the period though, the invention of the compartmented wheel cannot be traced to any particular Hellenistic engineer and may have been made in the late 4th century BC in a rural context away from the metropolis of Alexandria.<ref name="Oleson 2000, 235">{{harvnb|Oleson|2000|pp=235}}</ref>

[[File:Archscrew2.jpg|thumb|left|Drainage wheel from Rio Tinto mines]]

The earliest depiction of a compartmented wheel is from a tomb painting in [[Ptolemaic Egypt]] which dates to the 2nd century BC. It shows a pair of yoked oxen driving the wheel via a [[sakia]] gear, which is here for the first time attested, too.<ref name="Oleson 2000, 234, 270">{{harvnb|Oleson|2000|pp=234, 270}}</ref> The Greek sakia gear system is already shown fully developed to the point that "modern Egyptian devices are virtually identical".<ref name="Oleson 2000, 234, 270"/> It is assumed that the scientists of the [[Musaeum at Alexandria|Museum of Alexandria]], at the time the most active Greek research center, may have been involved in its invention.<ref>{{harvnb|Oleson|2000|pp=271f.}}</ref> An episode from the [[Alexandrian War]] in 48 BC tells of how Caesar's enemies employed geared waterwheels to pour sea water from elevated places on the position of the trapped Romans.<ref>{{harvnb|Oleson|2000|p=271}}</ref>

Around 300 AD, the [[noria]] was finally introduced when the wooden compartments were replaced with inexpensive ceramic pots that were tied to the outside of an open-framed wheel.<ref name="Oleson 2000, 235"/>

===== Watermilling =====
[[File:Roda de Vitruvi.jpg|thumb|upright|left|[[Vitruvius]]' undershot-wheeled watermill (reconstruction)]]

Taking indirect evidence into account from the work of the Greek technician [[Apollonius of Perge]], the British historian of technology M.J.T. Lewis dates the appearance of the vertical-axle watermill to the early 3rd century BC, and the horizontal-axle watermill to around 240 BC, with [[Byzantium]] and [[Alexandria]] as the assigned places of invention.<ref>{{harvnb|Wikander|2000|p=396f.}}; {{harvnb|Donners|Waelkens|Deckers|2002|p=11}}; {{harvnb|Wilson|2002|pp=7f.}}</ref> A watermill is reported by the Greek geographer [[Strabon]] ({{Circa|64 BC|AD 24}}) to have existed sometime before 71 BC in the palace of the [[Kingdom of Pontus|Pontian]] king [[Mithradates VI Eupator]], but its exact construction cannot be gleaned from the text (XII, 3, 30 C 556).<ref>{{harvnb|Wikander|1985|p=160}}; {{harvnb|Wikander|2000|p=396}}</ref>

The first clear description of a geared watermill offers the late 1st century BC Roman architect Vitruvius who tells of the sakia gearing system as being applied to a watermill.<ref>{{harvnb|Oleson|2000|pp=234, 269}}</ref> Vitruvius's account is particularly valuable in that it shows how the watermill came about, namely by the combination of the separate Greek inventions of the toothed gear and the waterwheel into one effective mechanical system for harnessing water power.<ref>{{harvnb|Oleson|2000|pp=269−271}}</ref> Vitruvius' waterwheel is described as being immersed with its lower end in the watercourse so that its paddles could be driven by the velocity of the running water (X, 5.2).<ref>{{harvnb|Wikander|2000|p=373f.}}; {{harvnb|Donners|Waelkens|Deckers|2002|p=12}}</ref>

[[File:Römische Sägemühle.svg|thumb|200px|Scheme of the Roman [[Hierapolis sawmill]], [[Asia Minor]], powered by a breastshot wheel]]

About the same time, the overshot wheel appears for the first time in a poem by [[Antipater of Thessalonica]], which praises it as a labour-saving device (IX, 418.4–6).<ref>{{harvnb|Wikander|2000|p=375}}; {{harvnb|Donners|Waelkens|Deckers|2002|p=13}}</ref> The motif is also taken up by [[Lucretius]] (ca. 99–55 BC) who likens the rotation of the waterwheel to the motion of the stars on the firmament (V 516).<ref>{{harvnb|Donners|Waelkens|Deckers|2002|p=11}}; {{harvnb|Oleson|2000|p=236}}</ref> The third horizontal-axled type, the breastshot waterwheel, comes into archaeological evidence by the late 2nd century AD context in [[Les Martres-de-Veyre|central Gaul]].<ref>{{harvnb|Wikander|2000|p=375}}</ref> Most excavated Roman watermills were equipped with one of these wheels which, although more complex to construct, were much more efficient than the vertical-axle waterwheel.<ref>{{harvnb|Donners|Waelkens|Deckers|2002|pp=12f.}}</ref> In the 2nd century AD [[Barbegal aqueduct and mill|Barbegal watermill complex]] a series of sixteen overshot wheels was fed by an artificial aqueduct, a proto-industrial grain factory which has been referred to as "the greatest known concentration of mechanical power in the ancient world".<ref>{{harvnb|Greene|2000|p=39}}</ref>

In [[Africa Province|Roman North Africa]], several installations from around 300 AD were found where vertical-axle waterwheels fitted with angled blades were installed at the bottom of a water-filled, circular shaft. The water from the mill-race which entered tangentially the pit created a swirling water column that made the fully submerged wheel act like true [[water turbine]]s, the earliest known to date.<ref name="Roman helix-turbine mill">{{harvnb|Wilson|1995|pp=507f.}}; {{harvnb|Wikander|2000|p=377}}; {{harvnb|Donners|Waelkens|Deckers|2002|p=13}}</ref>

===== Navigation =====
[[File:De Rebus Bellicis, XVth Century Miniature.JPG|thumb|right|Ox-powered Roman paddle wheel boat from a 15th-century copy of ''[[De Rebus Bellicis]]'']]

Apart from its use in milling and water-raising, ancient engineers applied the paddled waterwheel for [[automaton]]s and in navigation. Vitruvius (X 9.5–7) describes multi-geared paddle wheels working as a ship [[odometer]], the earliest of its kind. The first mention of paddle wheels as a means of propulsion comes from the  4th–5th century military treatise ''[[De Rebus Bellicis]]'' (chapter XVII), where the anonymous Roman author describes an ox-driven paddle-wheel warship.<ref>De Rebus Bellicis (anon.), chapter XVII, text edited by Robert Ireland, in: ''BAR International Series'' 63, part 2, p. 34</ref>