Watermill
Encyclopedia
A watermill is a structure that uses a water wheel
Water wheel
A water wheel is a machine for converting the energy of free-flowing or falling water into useful forms of power. A water wheel consists of a large wooden or metal wheel, with a number of blades or buckets arranged on the outside rim forming the driving surface...

 or turbine
Water turbine
A water turbine is a rotary engine that takes energy from moving water.Water turbines were developed in the 19th century and were widely used for industrial power prior to electrical grids. Now they are mostly used for electric power generation. They harness a clean and renewable energy...

 to drive a mechanical process such as flour
Flour
Flour is a powder which is made by grinding cereal grains, other seeds or roots . It is the main ingredient of bread, which is a staple food for many cultures, making the availability of adequate supplies of flour a major economic and political issue at various times throughout history...

, lumber
Lumber
Lumber or timber is wood in any of its stages from felling through readiness for use as structural material for construction, or wood pulp for paper production....

 or textile
Textile
A textile or cloth is a flexible woven material consisting of a network of natural or artificial fibres often referred to as thread or yarn. Yarn is produced by spinning raw fibres of wool, flax, cotton, or other material to produce long strands...

 production, or metal shaping (rolling, grinding or wire drawing
Wire drawing
Wire drawing is a metalworking process used to reduce the cross-section of a wire by pulling the wire through a single, or series of, drawing die. There are many applications for wire drawing, including electrical wiring, cables, tension-loaded structural components, springs, paper clips, spokes...

).

History

There are two basic types of watermills, one powered by a vertical-waterwheel via a gearing mechanism, and the other equipped by a horizontal-waterwheel without such a mechanism. The former type can be further divided, depending on where the water hits the wheel paddles, into undershot, overshot, breastshot and reverse shot waterwheel mills.

Classical Antiquity

The Greeks
Hellenistic civilization
Hellenistic civilization represents the zenith of Greek influence in the ancient world from 323 BCE to about 146 BCE...

 invented the two main components of watermills, the waterwheel and toothed gearing, and were, along with the Romans
Roman Empire
The Roman Empire was the post-Republican period of the ancient Roman civilization, characterised by an autocratic form of government and large territorial holdings in Europe and around the Mediterranean....

, the first to operate undershot, overshot and breastshot waterwheel mills.

The earliest evidence of a water-driven wheel is probably the Perachora
Perachora
Perachora, also Perahora or Perakhora is an inland settlement in the Loutraki-Perachoras municipality of the Corinthia prefecture in the periphery of Peloponnese in Greece. It is located about 7 km NW of the town of Loutraki in a hilly environment surrounded by higher elevation of the Geraneia...

 wheel (3rd c. BC), in Greece
Greece
Greece , officially the Hellenic Republic , and historically Hellas or the Republic of Greece in English, is a country in southeastern Europe....

. The earliest written reference is in the technical treatises Pneumatica and Parasceuastica of the Greek engineer Philo of Byzantium
Philo of Byzantium
Philo of Byzantium , also known as Philo Mechanicus, was a Greek engineer and writer on mechanics, who lived during the latter half of the 3rd century BC...

 (ca. 280−220 BC). The British historian of technology M.J.T. Lewis has shown that those portions of Philo of Byzantium's mechanical treatise which describe water wheels and which have been previously regarded as later Arabic
Arabic language
Arabic is a name applied to the descendants of the Classical Arabic language of the 6th century AD, used most prominently in the Quran, the Islamic Holy Book...

 interpolations, actually date back to the Greek 3rd century BC original. The sakia gear
Sakia
A sakia , tympanum or tablia is a water wheel, somewhat similar to a noria, and used primarily in Egypt. It is a large hollow wheel, normally made of galvanized sheet steel, with scoops or buckets at the periphery...

 is, already fully developed, for the first time attested in a 2nd century BC Hellenistic wall painting in Ptolemaic Egypt
Ptolemaic Egypt
Ptolemaic Egypt began when Ptolemy I Soter invaded Egypt and declared himself Pharaoh of Egypt in 305 BC and ended with the death of queen Cleopatra VII of Egypt and the Roman conquest in 30 BC. The Ptolemaic Kingdom was a powerful Hellenistic state, extending from southern Syria in the east, to...

.

Lewis assigns the date of the invention of the horizontal-wheeled mill to the Greek colony of Byzantium
Byzantium
Byzantium was an ancient Greek city, founded by Greek colonists from Megara in 667 BC and named after their king Byzas . The name Byzantium is a Latinization of the original name Byzantion...

 in the first half of 3rd century BC, and that of the vertical-wheeled mill to Ptolemaic Alexandria
Alexandria
Alexandria is the second-largest city of Egypt, with a population of 4.1 million, extending about along the coast of the Mediterranean Sea in the north central part of the country; it is also the largest city lying directly on the Mediterranean coast. It is Egypt's largest seaport, serving...

 around 240 BC.

The Greek geographer Strabon reports in his Geography a water-powered grain-mill to have existed near the palace of king Mithradates VI Eupator at Cabira
Cabira
Cabira , a place in Pontus, at the base of the range of Paryadres, about 150 stadia south of Eupatoria or Magnopolis, which was at the junction of the Iris and the Lycus. Eupatoria was in the midst of the plain, but Cabira, as Strabo says , was at the base of the Paryadres...

, Asia Minor
Asia Minor
Asia Minor is a geographical location at the westernmost protrusion of Asia, also called Anatolia, and corresponds to the western two thirds of the Asian part of Turkey...

, before 71 BC.

The Roman engineer Vitruvius
Vitruvius
Marcus Vitruvius Pollio was a Roman writer, architect and engineer, active in the 1st century BC. He is best known as the author of the multi-volume work De Architectura ....

 has the first technical description of a watermill, dated to 40/10 BC; the device is fitted with an undershot wheel and power is transmitted via a gearing mechanism
Saqiya
Saqiya was a village in Palestine away from Jaffa, depopulated in 1948.-Location:The village was located east of Jaffa, above sea level, on uneven land in the central coastal plain...

. He also seems to indicate the existence of water-powered kneading
Kneading
Kneading is a process in the making of bread or pasta dough, used to mix together the ingredients and add strength to the final product. Its importance lies in the mixing of flour with water. When these two ingredients are combined and kneaded, the gliadin and glutenin proteins in the flour expand...

 machines.

The Greek epigrammatist Antipater of Thessalonica
Antipater of Thessalonica
Antipater of Thessalonica was the author of over a hundred epigrams in the Greek Anthology. He is the most copious and perhaps the most interesting of the Augustan epigrammatists...

 tells of an advanced overshot wheel mill around 20 BC/10 AD. He praised for its use in grinding grain and the reduction of human labour:
The Roman encyclopedist Pliny
Pliny the Elder
Gaius Plinius Secundus , better known as Pliny the Elder, was a Roman author, naturalist, and natural philosopher, as well as naval and army commander of the early Roman Empire, and personal friend of the emperor Vespasian...

 mentions in his Naturalis Historia
Naturalis Historia
The Natural History is an encyclopedia published circa AD 77–79 by Pliny the Elder. It is one of the largest single works to have survived from the Roman Empire to the modern day and purports to cover the entire field of ancient knowledge, based on the best authorities available to Pliny...

of around 70 AD water-powered trip hammer
Trip hammer
A trip hammer, also known as a helve hammer, is a massive powered hammer used in:* agriculture to facilitate the labor of pounding, decorticating and polishing of grain;...

s operating in the greater part of Italy. There is evidence of a fulling mill in 73/4 AD in Antioch
Antioch
Antioch on the Orontes was an ancient city on the eastern side of the Orontes River. It is near the modern city of Antakya, Turkey.Founded near the end of the 4th century BC by Seleucus I Nicator, one of Alexander the Great's generals, Antioch eventually rivaled Alexandria as the chief city of the...

, Roman Syria.

It is likely that a water-powered stamp mill
Stamp mill
A stamp mill is a type of mill machine that crushes material by pounding rather than grinding, either for further processing or for extraction of metallic ores. Breaking material down is a type of unit operation....

 was used at Dolaucothi to crush gold
Gold
Gold is a chemical element with the symbol Au and an atomic number of 79. Gold is a dense, soft, shiny, malleable and ductile metal. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. Chemically, gold is a...

-bearing quartz
Quartz
Quartz is the second-most-abundant mineral in the Earth's continental crust, after feldspar. It is made up of a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2. There are many different varieties of quartz,...

, with a possible date of late 1st century to early 2nd century. The stamps were operated as a batch of four working against a large conglomerate
Conglomerate (geology)
A conglomerate is a rock consisting of individual clasts within a finer-grained matrix that have become cemented together. Conglomerates are sedimentary rocks consisting of rounded fragments and are thus differentiated from breccias, which consist of angular clasts...

 block, now known as Carreg Pumpsaint. Similar anvil stones have been found at other Roman mines across Europe, especially in Spain and Portugal.

The 1st century AD multiple mill complex of Barbegal
Barbegal aqueduct and mill
The Barbegal aqueduct and mill is a Roman watermill complex located on the territory of the commune of Fontvieille, near the town of Arles, in southern France. The complex has been referred to as "the greatest known concentration of mechanical power in the ancient world"...

 in southern France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

 has been described as "the greatest known concentration of mechanical power in the ancient world". It featured 16 overshot waterwheels to power an equal number of flour
Flour
Flour is a powder which is made by grinding cereal grains, other seeds or roots . It is the main ingredient of bread, which is a staple food for many cultures, making the availability of adequate supplies of flour a major economic and political issue at various times throughout history...

 mills. The capacity of the mills has been estimated at 4.5 tons of flour
Flour
Flour is a powder which is made by grinding cereal grains, other seeds or roots . It is the main ingredient of bread, which is a staple food for many cultures, making the availability of adequate supplies of flour a major economic and political issue at various times throughout history...

 per day, sufficient to supply enough bread for the 12,500 inhabitants occupying the town of Arelate
Arles
Arles is a city and commune in the south of France, in the Bouches-du-Rhône department, of which it is a subprefecture, in the former province of Provence....

 at that time. A similar mill complex existed on the Janiculum
Janiculum
The Janiculum is a hill in western Rome, Italy. Although the second-tallest hill in the contemporary city of Rome, the Janiculum does not figure among the proverbial Seven Hills of Rome, being west of the Tiber and outside the boundaries of the ancient city.-Sights:The Janiculum is one of the...

 hill, whose supply of flour for Rome
Rome
Rome is the capital of Italy and the country's largest and most populated city and comune, with over 2.7 million residents in . The city is located in the central-western portion of the Italian Peninsula, on the Tiber River within the Lazio region of Italy.Rome's history spans two and a half...

's population was judged by emperor Aurelian
Aurelian
Aurelian , was Roman Emperor from 270 to 275. During his reign, he defeated the Alamanni after a devastating war. He also defeated the Goths, Vandals, Juthungi, Sarmatians, and Carpi. Aurelian restored the Empire's eastern provinces after his conquest of the Palmyrene Empire in 273. The following...

 important enough to be included in the Aurelian walls
Aurelian Walls
The Aurelian Walls is a line of city walls built between 271 and 275 in Rome, Italy, during the reign of the Roman Emperors Aurelian and Probus....

 in the late 3rd century.

A breastshot wheel mill dating to the late 2nd century AD was excavated at Les Martres-de-Veyre
Les Martres-de-Veyre
Les Martres-de-Veyre is a commune in the Puy-de-Dôme department in Auvergne in central France.-References:*...

, France.
The 3rd century AD Hierapolis water-powered stone sawmill is the earliest known machine to incorporate a crank
Crank (mechanism)
A crank is an arm attached at right angles to a rotating shaft by which reciprocating motion is imparted to or received from the shaft. It is used to change circular into reciprocating motion, or reciprocating into circular motion. The arm may be a bent portion of the shaft, or a separate arm...

 and connecting rod
Connecting rod
In a reciprocating piston engine, the connecting rod or conrod connects the piston to the crank or crankshaft. Together with the crank, they form a simple mechanism that converts linear motion into rotating motion....

 mechanism. Further sawmills, also powered by crank and connecting rod mechanisms, are archaeologically attested for the 6th century water-powered stone sawmills at Gerasa and Ephesus
Ephesus
Ephesus was an ancient Greek city, and later a major Roman city, on the west coast of Asia Minor, near present-day Selçuk, Izmir Province, Turkey. It was one of the twelve cities of the Ionian League during the Classical Greek era...

. Literary references to water-powered marble
Marble
Marble is a metamorphic rock composed of recrystallized carbonate minerals, most commonly calcite or dolomite.Geologists use the term "marble" to refer to metamorphosed limestone; however stonemasons use the term more broadly to encompass unmetamorphosed limestone.Marble is commonly used for...

 saws in what is now Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

 can be found in Ausonius
Ausonius
Decimius Magnus Ausonius was a Latin poet and rhetorician, born at Burdigala .-Biography:Decimius Magnus Ausonius was born in Bordeaux in ca. 310. His father was a noted physician of Greek ancestry and his mother was descended on both sides from long-established aristocratic Gallo-Roman families...

 4th century poem Mosella. They also seem to be indicated about the same time by the Christian saint Gregory of Nyssa
Gregory of Nyssa
St. Gregory of Nyssa was a Christian bishop and saint. He was a younger brother of Basil the Great and a good friend of Gregory of Nazianzus. His significance has long been recognized in the Eastern Orthodox, Oriental Orthodox, Eastern Catholic and Roman Catholic branches of Christianity...

 from Anatolia
Anatolia
Anatolia is a geographic and historical term denoting the westernmost protrusion of Asia, comprising the majority of the Republic of Turkey...

, demonstrating a diversified use of water-power in many parts of the Roman Empire
Roman Empire
The Roman Empire was the post-Republican period of the ancient Roman civilization, characterised by an autocratic form of government and large territorial holdings in Europe and around the Mediterranean....

.

The earliest turbine
Water turbine
A water turbine is a rotary engine that takes energy from moving water.Water turbines were developed in the 19th century and were widely used for industrial power prior to electrical grids. Now they are mostly used for electric power generation. They harness a clean and renewable energy...

 mill was found in Chemtou
Chemtou
Chemtou or Chimtou is an ancient site in northwestern Tunisia, located 20 km from the city of Jendouba, near the Algerian border.Ancient Simitthu is known for its important marble quarries which were exploited from the 2nd century BC.The Chemtou Museum displays artifacts discovered in the...

 and Testour
Testour
Testour is a small town located in the north of Tunisia. The town is perched on the hills of Medjerda Valley, 20 km south-west of Medjez-el-Bab, the crossroads between Tunis, Béja, and the north of Tunisia...

, Roman North Africa, dating to the late 3rd or early 4th cent. AD. A possible water-powered furnace
Furnace
A furnace is a device used for heating. The name derives from Latin fornax, oven.In American English and Canadian English, the term furnace on its own is generally used to describe household heating systems based on a central furnace , and sometimes as a synonym for kiln, a device used in the...

 has been identified at Marseille
Marseille
Marseille , known in antiquity as Massalia , is the second largest city in France, after Paris, with a population of 852,395 within its administrative limits on a land area of . The urban area of Marseille extends beyond the city limits with a population of over 1,420,000 on an area of...

, France.

Mills were commonly used for grinding grain into flour (attested by Pliny the Elder
Pliny the Elder
Gaius Plinius Secundus , better known as Pliny the Elder, was a Roman author, naturalist, and natural philosopher, as well as naval and army commander of the early Roman Empire, and personal friend of the emperor Vespasian...

), but industrial uses as fulling
Fulling
Fulling or tucking or walking is a step in woolen clothmaking which involves the cleansing of cloth to eliminate oils, dirt, and other impurities, and making it thicker. The worker who does the job is a fuller, tucker, or walker...

 and sawing marble
Marble
Marble is a metamorphic rock composed of recrystallized carbonate minerals, most commonly calcite or dolomite.Geologists use the term "marble" to refer to metamorphosed limestone; however stonemasons use the term more broadly to encompass unmetamorphosed limestone.Marble is commonly used for...

 were also applied.

The Romans used both fixed and floating water wheels and introduced water power to other provinces of the Roman Empire
Roman Empire
The Roman Empire was the post-Republican period of the ancient Roman civilization, characterised by an autocratic form of government and large territorial holdings in Europe and around the Mediterranean....

. So-called 'Greek Mills' used water wheels with a horizontal wheel (and vertical shaft). A "Roman Mill" features a vertical wheel (on a horizontal shaft). Greek style mills are the older and simpler of the two designs, but only operate well with high water velocities and with small diameter millstones. Roman style mills are more complicated as they require gears to transmit the power from a shaft with a horizontal axis to one with a vertical axis.

Although to date only a few dozen Roman mills are archaeologically traced, the widespread use of aqueducts in the period suggests that many remain to be discovered. Recent excavations in Roman London, for example, have uncovered what appears to be a tide mill
Tide mill
A tide mill is a water mill driven by tidal rise and fall. A dam with a sluice is created across a suitable tidal inlet, or a section of river estuary is made into a reservoir. As the tide comes in, it enters the mill pond through a one way gate, and this gate closes automatically when the tide...

 together with a possible sequence of mills worked by an aqueduct running along the side of the River Fleet
River Fleet
The River Fleet is the largest of London's subterranean rivers. Its two headwaters are two streams on Hampstead Heath; each is now dammed into a series of ponds made in the 18th century, the Hampstead Ponds and the Highgate Ponds. At the south edge of Hampstead Heath these two streams flow...

.

In 537 AD, ship mill
Ship mill
The ship-mill grinder today is a rare type of watermill. Its first recorded use dates back to mid-6th century AD Italy.- Technology :...

s were ingeniously used by the East Roman general Belisarius
Belisarius
Flavius Belisarius was a general of the Byzantine Empire. He was instrumental to Emperor Justinian's ambitious project of reconquering much of the Mediterranean territory of the former Western Roman Empire, which had been lost less than a century previously....

, when the besieging Goths cut off the water supply for those mills. These floating mills had a wheel that was attached to a boat moored in a fast flowing river.


Middle Ages

Largely unaffected from the turbulent political events
Migration Period
The Migration Period, also called the Barbarian Invasions , was a period of intensified human migration in Europe that occurred from c. 400 to 800 CE. This period marked the transition from Late Antiquity to the Early Middle Ages...

 following the demise of the Western Roman Empire
Decline of the Roman Empire
The decline of the Roman Empire refers to the gradual societal collapse of the Western Roman Empire. Many theories of causality prevail, but most concern the disintegration of political, economic, military, and other social institutions, in tandem with foreign invasions and usurpers from within the...

, the importance of watermilling continued to grow under the new Germanic
Germanic peoples
The Germanic peoples are an Indo-European ethno-linguistic group of Northern European origin, identified by their use of the Indo-European Germanic languages which diversified out of Proto-Germanic during the Pre-Roman Iron Age.Originating about 1800 BCE from the Corded Ware Culture on the North...

 lords. The sharp rise in numbers of documented early medieval
Early Middle Ages
The Early Middle Ages was the period of European history lasting from the 5th century to approximately 1000. The Early Middle Ages followed the decline of the Western Roman Empire and preceded the High Middle Ages...

 watermills coincided with the appearance of new documentary genres (legal code
Legal code
A legal code is a body of law written by a governmental body, such as a U.S. state, a Canadian Province or German Bundesland or a municipality...

s, monastic
Monastery
Monastery denotes the building, or complex of buildings, that houses a room reserved for prayer as well as the domestic quarters and workplace of monastics, whether monks or nuns, and whether living in community or alone .Monasteries may vary greatly in size – a small dwelling accommodating only...

 charter
Charter
A charter is the grant of authority or rights, stating that the granter formally recognizes the prerogative of the recipient to exercise the rights specified...

s, hagiography
Hagiography
Hagiography is the study of saints.From the Greek and , it refers literally to writings on the subject of such holy people, and specifically to the biographies of saints and ecclesiastical leaders. The term hagiology, the study of hagiography, is also current in English, though less common...

) which were more inclined to address such a relatively mundane device than the ancient
Classical antiquity
Classical antiquity is a broad term for a long period of cultural history centered on the Mediterranean Sea, comprising the interlocking civilizations of ancient Greece and ancient Rome, collectively known as the Greco-Roman world...

 urban-centered literary class had been. This partly explains the relative abundance of medieval literary references to watermills compared to former times. Also, through Thirlage
Thirlage
Thirlage was the term used for the law in regard of the milling of grain for personal or other uses. Vassals in a feudal barony were thirled to their local mill owned by the feudal superior...

, they formed part of the feudal system and its associated bureaucracy.

Nevertheless, the quantitative growth of medieval evidence appears to be more than a mere reflection of the changing nature of surviving sources: by Carolingian times, references to watermills in the Frankish Realm
Carolingian Empire
Carolingian Empire is a historiographical term which has been used to refer to the realm of the Franks under the Carolingian dynasty in the Early Middle Ages. This dynasty is seen as the founders of France and Germany, and its beginning date is based on the crowning of Charlemagne, or Charles the...

 had become "innumerable", and at the time of the compilation of the Domesday Book
Domesday Book
Domesday Book , now held at The National Archives, Kew, Richmond upon Thames in South West London, is the record of the great survey of much of England and parts of Wales completed in 1086...

 (1086), there were 5,624 watermills in England alone, only 2% of which have not been located by modern archeological surveys. Later research estimates a less conservative number of 6,082, and it has been pointed out that this should be considered a minimum as the northern reaches of England were never properly recorded. In 1300, this number had risen to between 10,000 and 15,000. By the early 7th century, watermills were well established in Ireland
Ireland
Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...

, and began to spread from the former territory of the empire into the non-romanized parts of Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

 a century later. The introduction of the ship mill
Ship mill
The ship-mill grinder today is a rare type of watermill. Its first recorded use dates back to mid-6th century AD Italy.- Technology :...

 and tide mill
Tide mill
A tide mill is a water mill driven by tidal rise and fall. A dam with a sluice is created across a suitable tidal inlet, or a section of river estuary is made into a reservoir. As the tide comes in, it enters the mill pond through a one way gate, and this gate closes automatically when the tide...

 in the 6th century, both of which yet unattested for the ancient period, allowed for a flexible response to the changing water-level of rivers and the Atlantic Ocean
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...

, thus demonstrating the technological innovativeness of early medieval watermillers.

Tide mills

In recent years, a number of new archaeological finds has consecutively pushed back the date of the earliest tide mills, all of which were discovered on the Irish
Ireland
Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...

 coast: A 6th century vertical-wheeled tide mill was located at Killoteran near Waterford
Waterford
Waterford is a city in the South-East Region of Ireland. It is the oldest city in the country and fifth largest by population. Waterford City Council is the local government authority for the city and its immediate hinterland...

. A twin flume horizontal-wheeled tide mill dating to c. 630 was excavated on Little Island
Little Island, Cork
Little Island is mainly an industrial area to the east of Cork City, Ireland. It is no longer an island, since the northern channel separating it from the mainland has filled over. To the east and south is Cork Harbour; across a channel to the west is Fota Island.-Development:Many of Cork's...

. Alongside it, another tide mill was found which was powered by a vertical undershot wheel. The Nendrum Monastery mill
Nendrum Monastery mill
The Nendrum Monastery mill was a tide mill on an island in Strangford Lough in Northern Ireland. It is the earliest excavated tide mill, dating from 787. Its millstones are 830mm in diameter and the horizontal wheel is estimated to have developed 7/8HP at its peak. Remains of an earlier mill dated...

 from 787 was situated on an island in Strangford Lough
Strangford Lough
Strangford Lough, sometimes Strangford Loch, is a large sea loch or inlet in County Down, Northern Ireland. It is separated from the Irish Sea by the Ards Peninsula. The name Strangford is derived ; describing the fast-flowing narrows at its mouth...

 in Northern Ireland
Northern Ireland
Northern Ireland is one of the four countries of the United Kingdom. Situated in the north-east of the island of Ireland, it shares a border with the Republic of Ireland to the south and west...

. Its millstones are 830mm in diameter and the horizontal wheel is estimated to have developed 7—8 hp at its peak. Remains of an earlier mill dated at 619 were also found at the site.

Survey of industrial mills

In a 2005 survey the scholar Adam Lucas identified the following first appearances of various industrial mill types in Western Europe. Noticeable is the preeminent role of France in the introduction of new innovative uses of waterpower. However, he has drawn attention to the dearth of studies of the subject in several other countries.
First Appearance of Various Industrial Mills in Medieval Europe, AD 770-1443
Type of mill Date Country
Malt mill 770 France
Fulling mill 1080 France
Tanning mill ca. 1134 France
Forge mill ca. 1200 England, France
Tool-sharpening mill 1203 France
Hemp mill 1209 France
Paper mill
Paper mill
A paper mill is a factory devoted to making paper from vegetable fibres such as wood pulp, old rags and other ingredients using a Fourdrinier machine or other type of paper machine.- History :...

1238, 1273 Xativa, Spain
Bellows 1269, 1283 Medieval Hungary, France
Sawmill
Sawmill
A sawmill is a facility where logs are cut into boards.-Sawmill process:A sawmill's basic operation is much like those of hundreds of years ago; a log enters on one end and dimensional lumber exits on the other end....

ca. 1300 France
Ore-crushing mill 1317 Germany
Blast furnace
Blast furnace
A blast furnace is a type of metallurgical furnace used for smelting to produce industrial metals, generally iron.In a blast furnace, fuel and ore and flux are continuously supplied through the top of the furnace, while air is blown into the bottom of the chamber, so that the chemical reactions...

1384 France
Cutting and slitting mill
Slitting mill
The slitting mill was a watermill for slitting bars of iron into rods. The rods then were passed to nailers who made the rods into nails, by giving them a point and head....

1443 France

Ancient China

The waterwheel was found in China from 30 AD onwards, when it was used to power trip hammer
Trip hammer
A trip hammer, also known as a helve hammer, is a massive powered hammer used in:* agriculture to facilitate the labor of pounding, decorticating and polishing of grain;...

s, the bellows
Bellows
A bellows is a device for delivering pressurized air in a controlled quantity to a controlled location.Basically, a bellows is a deformable container which has an outlet nozzle. When the volume of the bellows is decreased, the air escapes through the outlet...

 in smelting iron
History of ferrous metallurgy
The history of ferrous metallurgy began far back in prehistory. The earliest surviving iron artifacts, from the 5th millennium BC in Iran and 2nd millennium BC in China, were made from meteoritic iron-nickel. It is not known when or where the smelting of iron from ores began, but by the end of the...

, and in one case, to mechanically rotate an armillary sphere
Armillary sphere
An armillary sphere is a model of objects in the sky , consisting of a spherical framework of rings, centred on Earth, that represent lines of celestial longitude and latitude and other astronomically important features such as the ecliptic...

 for astronomical observation
Chinese astronomy
Astronomy in China has a very long history, with historians considering that "they [the Chinese] were the most persistent and accurate observers of celestial phenomena anywhere in the world before the Arabs."...

 (see Zhang Heng
Zhang Heng
Zhang Heng was a Chinese astronomer, mathematician, inventor, geographer, cartographer, artist, poet, statesman, and literary scholar from Nanyang, Henan. He lived during the Eastern Han Dynasty of China. He was educated in the capital cities of Luoyang and Chang'an, and began his career as a...

). Although Joseph Needham speculates that the water-powered millstone could have existed in Han China by the 1st century AD, there is no sufficient literary evidence for it until the 5th century. In 488 AD, the mathematician and engineer Zu Chongzhi
Zu Chongzhi
Zu Chongzhi , courtesy name Wenyuan , was a prominent Chinese mathematician and astronomer during the Liu Song and Southern Qi Dynasties.-Life and works:...

 had a watermill erected which was inspected by Emperor Wu of Southern Qi
Emperor Wu of Southern Qi
Emperor Wu of Southern Qi , personal name Xiao Ze , courtesy name Xuanyuan , nickname Long'er , was the second emperor of the Chinese Southern Qi Dynasty...

 (r. 482–493 AD). The engineer Yang Su of the Sui Dynasty
Sui Dynasty
The Sui Dynasty was a powerful, but short-lived Imperial Chinese dynasty. Preceded by the Southern and Northern Dynasties, it ended nearly four centuries of division between rival regimes. It was followed by the Tang Dynasty....

 (581–618 AD) was said to operate hundreds of them by the beginning of the 6th century. A source written in 612 AD mentions Buddhist monks
Bhikkhu
A Bhikkhu or Bhikṣu is an ordained male Buddhist monastic. A female monastic is called a Bhikkhuni Nepali: ). The life of Bhikkhus and Bhikkhunis is governed by a set of rules called the patimokkha within the vinaya's framework of monastic discipline...

 arguing over the revenues gained from watermills. The Tang Dynasty
Tang Dynasty
The Tang Dynasty was an imperial dynasty of China preceded by the Sui Dynasty and followed by the Five Dynasties and Ten Kingdoms Period. It was founded by the Li family, who seized power during the decline and collapse of the Sui Empire...

 (618–907 AD) 'Ordinances of the Department of Waterways' written in 737 AD stated that watermills should not interrupt riverine transport and in some cases were restricted to use in certain seasons of the year. From other Tang-era sources of the 8th century, it is known that these ordinances were taken very seriously, as the government demolished many watermills owned by great families, merchants, and Buddhist abbeys that failed to acknowledge ordinances or meet government regulations. A eunuch serving Emperor Xuanzong of Tang
Emperor Xuanzong of Tang
Emperor Xuanzong of Tang , also commonly known as Emperor Ming of Tang , personal name Li Longji , known as Wu Longji from 690 to 705, was the seventh emperor of the Tang dynasty in China, reigning from 712 to 756. His reign of 43 years was the longest during the Tang Dynasty...

 (r. 712–756 AD) owned a watermill by 748 AD which employed five waterwheels that ground 300 bushel
Bushel
A bushel is an imperial and U.S. customary unit of dry volume, equivalent in each of these systems to 4 pecks or 8 gallons. It is used for volumes of dry commodities , most often in agriculture...

s of wheat a day. By 610 or 670 AD, the watermill was introduced to Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

 via Korean Peninsula
Korean Peninsula
The Korean Peninsula is a peninsula in East Asia. It extends southwards for about 684 miles from continental Asia into the Pacific Ocean and is surrounded by the Sea of Japan to the south, and the Yellow Sea to the west, the Korea Strait connecting the first two bodies of water.Until the end of...

. It also became known in Tibet
Tibet
Tibet is a plateau region in Asia, north-east of the Himalayas. It is the traditional homeland of the Tibetan people as well as some other ethnic groups such as Monpas, Qiang, and Lhobas, and is now also inhabited by considerable numbers of Han and Hui people...

 by at least 641 AD.

Ancient India

According to Greek historical tradition, India received water-mills from the Roman Empire in the early 4th century AD when a certain Metrodoros introduced "water-mills and baths, unknown among them [the Brahmans] till then".

Islamic world

Muslim engineers adopted the Greek watermill technology from the Byzantine Empire
Byzantine Empire
The Byzantine Empire was the Eastern Roman Empire during the periods of Late Antiquity and the Middle Ages, centred on the capital of Constantinople. Known simply as the Roman Empire or Romania to its inhabitants and neighbours, the Empire was the direct continuation of the Ancient Roman State...

, where it had been applied for centuries in those provinces conquered by the Muslims, including modern-day Syria
Syria
Syria , officially the Syrian Arab Republic , is a country in Western Asia, bordering Lebanon and the Mediterranean Sea to the West, Turkey to the north, Iraq to the east, Jordan to the south, and Israel to the southwest....

, Jordan
Jordan
Jordan , officially the Hashemite Kingdom of Jordan , Al-Mamlaka al-Urduniyya al-Hashemiyya) is a kingdom on the East Bank of the River Jordan. The country borders Saudi Arabia to the east and south-east, Iraq to the north-east, Syria to the north and the West Bank and Israel to the west, sharing...

, Israel
Israel
The State of Israel is a parliamentary republic located in the Middle East, along the eastern shore of the Mediterranean Sea...

, Algeria
Algeria
Algeria , officially the People's Democratic Republic of Algeria , also formally referred to as the Democratic and Popular Republic of Algeria, is a country in the Maghreb region of Northwest Africa with Algiers as its capital.In terms of land area, it is the largest country in Africa and the Arab...

, Tunisia
Tunisia
Tunisia , officially the Tunisian RepublicThe long name of Tunisia in other languages used in the country is: , is the northernmost country in Africa. It is a Maghreb country and is bordered by Algeria to the west, Libya to the southeast, and the Mediterranean Sea to the north and east. Its area...

, Morocco
Morocco
Morocco , officially the Kingdom of Morocco , is a country located in North Africa. It has a population of more than 32 million and an area of 710,850 km², and also primarily administers the disputed region of the Western Sahara...

, and Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...

 (see List of ancient watermills).

The industrial
Industry
Industry refers to the production of an economic good or service within an economy.-Industrial sectors:There are four key industrial economic sectors: the primary sector, largely raw material extraction industries such as mining and farming; the secondary sector, involving refining, construction,...

 uses of watermills in the Islamic world date back to the 7th century, while horizontal-wheeled and vertical-wheeled watermills were both in widespread use by the 9th century. A variety of industrial watermills were used in the Islamic world, including gristmill
Gristmill
The terms gristmill or grist mill can refer either to a building in which grain is ground into flour, or to the grinding mechanism itself.- Early history :...

s, huller
Huller
A rice huller or rice husker is an agricultural machine used to automate the process of removing the chaff and the outer husks of rice grain. Throughout history, there have been numerous techniques to hull rice. Traditionally, it would be pounded using some form of mortar and pestle. Machinery...

s, sawmill
Sawmill
A sawmill is a facility where logs are cut into boards.-Sawmill process:A sawmill's basic operation is much like those of hundreds of years ago; a log enters on one end and dimensional lumber exits on the other end....

s, shipmills, stamp mill
Stamp mill
A stamp mill is a type of mill machine that crushes material by pounding rather than grinding, either for further processing or for extraction of metallic ores. Breaking material down is a type of unit operation....

s, steel mill
Steel mill
A steel mill or steelworks is an industrial plant for the manufacture of steel.Steel is an alloy of iron and carbon. It is produced in a two-stage process. First, iron ore is reduced or smelted with coke and limestone in a blast furnace, producing molten iron which is either cast into pig iron or...

s, sugar mills
Sugar refinery
A sugar refinery is a factory which refines raw sugar.Many cane sugar mills produce raw sugar, i.e. sugar with more colour and therefore more impurities than the white sugar which is normally consumed in households and used as an ingredient in soft drinks, cookies and so forth...

, and tide mill
Tide mill
A tide mill is a water mill driven by tidal rise and fall. A dam with a sluice is created across a suitable tidal inlet, or a section of river estuary is made into a reservoir. As the tide comes in, it enters the mill pond through a one way gate, and this gate closes automatically when the tide...

s. By the 11th century, every province throughout the Islamic world had these industrial watermills in operation, from al-Andalus
Al-Andalus
Al-Andalus was the Arabic name given to a nation and territorial region also commonly referred to as Moorish Iberia. The name describes parts of the Iberian Peninsula and Septimania governed by Muslims , at various times in the period between 711 and 1492, although the territorial boundaries...

 and North Africa
North Africa
North Africa or Northern Africa is the northernmost region of the African continent, linked by the Sahara to Sub-Saharan Africa. Geopolitically, the United Nations definition of Northern Africa includes eight countries or territories; Algeria, Egypt, Libya, Morocco, South Sudan, Sudan, Tunisia, and...

 to the Middle East
Middle East
The Middle East is a region that encompasses Western Asia and Northern Africa. It is often used as a synonym for Near East, in opposition to Far East...

 and Central Asia
Central Asia
Central Asia is a core region of the Asian continent from the Caspian Sea in the west, China in the east, Afghanistan in the south, and Russia in the north...

. Muslim and Middle Eastern Christian engineers also used crankshaft
Crankshaft
The crankshaft, sometimes casually abbreviated to crank, is the part of an engine which translates reciprocating linear piston motion into rotation...

s and water turbine
Water turbine
A water turbine is a rotary engine that takes energy from moving water.Water turbines were developed in the 19th century and were widely used for industrial power prior to electrical grids. Now they are mostly used for electric power generation. They harness a clean and renewable energy...

s, gear
Gear
A gear is a rotating machine part having cut teeth, or cogs, which mesh with another toothed part in order to transmit torque. Two or more gears working in tandem are called a transmission and can produce a mechanical advantage through a gear ratio and thus may be considered a simple machine....

s in watermills and water-raising machine
Machine
A machine manages power to accomplish a task, examples include, a mechanical system, a computing system, an electronic system, and a molecular machine. In common usage, the meaning is that of a device having parts that perform or assist in performing any type of work...

s, and dam
Dam
A dam is a barrier that impounds water or underground streams. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. Hydropower and pumped-storage hydroelectricity are...

s as a source of water, used to provide additional power to watermills and water-raising machines. Fulling mills, and steel mills may have spread from Al-Andalus
Al-Andalus
Al-Andalus was the Arabic name given to a nation and territorial region also commonly referred to as Moorish Iberia. The name describes parts of the Iberian Peninsula and Septimania governed by Muslims , at various times in the period between 711 and 1492, although the territorial boundaries...

 to Christian Spain in the 12th century. Industrial watermills were also employed in large factory
Factory
A factory or manufacturing plant is an industrial building where laborers manufacture goods or supervise machines processing one product into another. Most modern factories have large warehouses or warehouse-like facilities that contain heavy equipment used for assembly line production...

 complexes built in al-Andalus between the 11th and 13th centuries.

The engineers of the Islamic world used several solutions to achieve the maximum output from a watermill. One solution was to mount them to pier
Pier
A pier is a raised structure, including bridge and building supports and walkways, over water, typically supported by widely spread piles or pillars...

s of bridge
Bridge
A bridge is a structure built to span physical obstacles such as a body of water, valley, or road, for the purpose of providing passage over the obstacle...

s to take advantage of the increased flow. Another solution was the shipmill, a type of watermill powered by water wheels mounted on the sides of ship
Ship
Since the end of the age of sail a ship has been any large buoyant marine vessel. Ships are generally distinguished from boats based on size and cargo or passenger capacity. Ships are used on lakes, seas, and rivers for a variety of activities, such as the transport of people or goods, fishing,...

s moored in midstream
Midstream
The petroleum industry is usually divided into three major components: upstream, midstream and downstream. Midstream operations are usually included in the downstream category....

. This technique was employed along the Tigris
Tigris
The Tigris River is the eastern member of the two great rivers that define Mesopotamia, the other being the Euphrates. The river flows south from the mountains of southeastern Turkey through Iraq.-Geography:...

 and Euphrates
Euphrates
The Euphrates is the longest and one of the most historically important rivers of Western Asia. Together with the Tigris, it is one of the two defining rivers of Mesopotamia...

 rivers in 10th century Iraq
Iraq
Iraq ; officially the Republic of Iraq is a country in Western Asia spanning most of the northwestern end of the Zagros mountain range, the eastern part of the Syrian Desert and the northern part of the Arabian Desert....

, where large shipmills made of teak
Teak
Teak is the common name for the tropical hardwood tree species Tectona grandis and its wood products. Tectona grandis is native to south and southeast Asia, mainly India, Indonesia, Malaysia, and Burma, but is naturalized and cultivated in many countries, including those in Africa and the...

 and iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...

 could produce 10 ton
Ton
The ton is a unit of measure. It has a long history and has acquired a number of meanings and uses over the years. It is used principally as a unit of weight, and as a unit of volume. It can also be used as a measure of energy, for truck classification, or as a colloquial term.It is derived from...

s of flour from corn
Gristmill
The terms gristmill or grist mill can refer either to a building in which grain is ground into flour, or to the grinding mechanism itself.- Early history :...

 every day for the granary
Granary
A granary is a storehouse for threshed grain or animal feed. In ancient or primitive granaries, pottery is the most common use of storage in these buildings. Granaries are often built above the ground to keep the stored food away from mice and other animals.-Early origins:From ancient times grain...

 in Baghdad
Baghdad
Baghdad is the capital of Iraq, as well as the coterminous Baghdad Governorate. The population of Baghdad in 2011 is approximately 7,216,040...

.

Operation of a watermill

Typically, water is diverted from a river
River
A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names, including...

 or impoundment
Dam
A dam is a barrier that impounds water or underground streams. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. Hydropower and pumped-storage hydroelectricity are...

 or mill pond to a turbine or water wheel, along a channel or pipe (variously known as a flume
Flume
A flume is an open artificial water channel, in the form of a gravity chute, that leads water from a diversion dam or weir completely aside a natural flow. Often, the flume is an elevated box structure that follows the natural contours of the land. These have been extensively used in hydraulic...

, head race, mill race
Mill race
A mill race, raceway or mill lade is the current or channel of a stream, especially one for conducting water to or from a water wheel or other device for utilizing its energy...

, leat
Leat
A leat is the name, common in the south and west of England and in Wales, for an artificial watercourse or aqueduct dug into the ground, especially one supplying water to a watermill or its mill pond...

, leet, lade (Scots) or penstock
Penstock
A penstock is a sluice or gate or intake structure that controls water flow, or an enclosed pipe that delivers water to hydraulic turbines and sewerage systems. It is a term that has been inherited from the technology of wooden watermills....

). The force of the water's movement drives the blades of a wheel or turbine, which in turn rotates an axle that drives the mill's other machinery. Water leaving the wheel or turbine is drained through a tail race, but this channel may also be the head race of yet another wheel, turbine or mill. The passage of water is controlled by sluice
Sluice
A sluice is a water channel that is controlled at its head by a gate . For example, a millrace is a sluice that channels water toward a water mill...

 gates that allow maintenance and some measure of flood
Flood
A flood is an overflow of an expanse of water that submerges land. The EU Floods directive defines a flood as a temporary covering by water of land not normally covered by water...

 control; large mill complexes may have dozens of sluices controlling complicated interconnected races that feed multiple buildings and industrial processes.
Watermills can be divided into two kinds, one with a horizontal waterwheel on a vertical axle, and the other with a vertical wheel on a horizontal axle. The oldest of these were horizontal mills in which the force of the water, striking a simple paddle wheel set horizontally in line with the flow turned a runner stone balanced on the rynd
Rynd
A millrind or simply rind is an iron support, usually four-armed or cross-shaped, for the turning stone in a pair of millstones. It is sometimes spelled millrynd or rynd....

 which is atop a shaft leading directly up from the wheel. The bedstone
Bedstone
Bedstone is a small village and civil parish in Shropshire, England, close to the borders of Herefordshire and Wales.The village is approximately 1½ miles from the railway stations at Hopton Heath and Bucknell and is situated just off the B4367 road.- Norman Origin :Its church dates back to...

 does not turn. The problem with this type of mill arose from the lack of gearing; the speed of the water directly set the maximum speed of the runner stone which, in turn, set the rate of milling.

Most watermills in Britain and the United States of America had a vertical waterwheel, one of three kinds: undershot, overshot and breast-shot. This produced rotary motion around a horizontal axis, which could be used (with cams) to lift hammers in a forge
Finery forge
Iron tapped from the blast furnace is pig iron, and contains significant amounts of carbon and silicon. To produce malleable wrought iron, it needs to undergo a further process. In the early modern period, this was carried out in a finery forge....

, fulling stocks in a fulling mill and so on. However, in corn mills rotation about a vertical axis was required to drive its stones. The horizontal rotation was converted into the vertical rotation by means of gearing, which also enabled the runner stones to turn faster than the waterwheel. The usual arrangement in British and American corn mills has been for the waterwheel to turn a horizontal shaft on which is also mounted a large pit wheel. This meshes with the wallower, mounted on a vertical shaft, which turns the (larger) great spur wheel (mounted on the same shaft). This large face wheel, set with pegs, in turn, turned a smaller wheel (such as a lantern gear) known as a stone nut, which was attached to the shaft that drove the runner stone. The number of runner stones that could be turned depended directly upon the supply of water available. As waterwheel technology improved mills became more efficient, and by the 19th century, it was common for the great spur wheel to drive several stone nuts, so that a single water wheel could drive as many as four stones. Each step in the process increased the gear ratio which increased the maximum speed of the runner stone. Adjusting the sluice gate and thus the flow of the water past the main wheel allowed the miller to compensate for seasonal variations in the water supply. Finer speed adjustment was made during the milling process by tentering, that is, adjusting the gap between the stones according to the water flow, the type of grain being milled, and the grade of flour required.

In many mills (including the earliest) the great spur wheel turned only one stone, but there might be several mills under one roof. The earliest illustriation of a single waterwheel driving more than one set of stones was drawn by Henry Beighton
Henry Beighton
Henry Beighton was an English engineer and surveyor.He was born at Chilvers Coton near Nuneaton, Warwickshire and worked in the neighbouring village of Griff. In 1717, he published an engraving of the Newcomen engine erected there in 1714 by Thomas Newcomen. In 1718 he erected one at Oxclose...

 in 1723 and published in 1744 by J. T. Desaguliers
John Theophilus Desaguliers
John Theophilus Desaguliers was a natural philosopher born in France. He was a member of the Royal Society of London beginning 29 July 1714. He was presented with the Royal Society's highest honour, the Copley Medal, in 1734, 1736 and 1741, with the 1741 award being for his discovery of the...

.
The overshot wheel was a later innovation in waterwheels and was around two and a half times more efficient than the undershot. The undershot wheel, in which the main water wheel is simply set into the flow of the mill race, suffers from an inherent inefficiency stemming from the fact that the wheel itself, entering the water behind the main thrust of the flow driving the wheel, followed by the lift of the wheel out of the water ahead of the main thrust, actually impedes its own operation. The overshot wheel solves this problem by bringing the water flow to the top of the wheel. The water fills buckets built into the wheel, rather than the simple paddle wheel design of undershot wheels. As the buckets fill, the weight of the water starts to turn the wheel. The water spills out of the bucket on the down side into a spillway leading back to river. Since the wheel itself is set above the spillway, the water never impedes the speed of the wheel. The impulse of the water on the wheel is also harnessed in addition to the weight of the water once in the buckets. Overshot wheels require the construction of a dam on the river above the mill and a more elaborate millpond, sluice gate, mill race and spillway or tailrace.

Toward the end of the 19th century, the invention of the Pelton wheel
Pelton wheel
The Pelton wheel is an impulse turbine which is among the most efficient types of water turbines. It was invented by Lester Allan Pelton in the 1870s. The Pelton wheel extracts energy from the impulse of moving water, as opposed to its weight like traditional overshot water wheel...

 encouraged some mill owners to replace over- and undershot wheels with penstocks and Pelton wheel turbines.

"Run of the river" schemes

Run of the river schemes do not divert water at all and usually involve undershot wheels, and some types of water wheel (usually overshot steel
Steel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...

 wheels) mount a toothed annular ring near the outer edge that drives machinery from a spur gear
Gear
A gear is a rotating machine part having cut teeth, or cogs, which mesh with another toothed part in order to transmit torque. Two or more gears working in tandem are called a transmission and can produce a mechanical advantage through a gear ratio and thus may be considered a simple machine....

 rather than taking power from the central axle
Axle
An axle is a central shaft for a rotating wheel or gear. On wheeled vehicles, the axle may be fixed to the wheels, rotating with them, or fixed to its surroundings, with the wheels rotating around the axle. In the former case, bearings or bushings are provided at the mounting points where the axle...

. However, the basic mode of operation remains the same; gravity drives machinery through the motion of flowing water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...

.

A different type of watermill is the tide mill
Tide mill
A tide mill is a water mill driven by tidal rise and fall. A dam with a sluice is created across a suitable tidal inlet, or a section of river estuary is made into a reservoir. As the tide comes in, it enters the mill pond through a one way gate, and this gate closes automatically when the tide...

. This mill might be of any kind, undershot, overshot or horizontal but it does not employ a river for its power source. Instead a mole or causeway is built across the mouth of a small bay. At low tide, gates in the mole are opened allowing the bay to fill with the incoming tide. At high tide the gates are closed, trapping the water inside. At a certain point a sluice gate in the mole can be opened allowing the draining water to drive a mill wheel or wheels. This is particularly effective in places where the tidal differential is very great, such as the Bay of Fundy
Bay of Fundy
The Bay of Fundy is a bay on the Atlantic coast of North America, on the northeast end of the Gulf of Maine between the Canadian provinces of New Brunswick and Nova Scotia, with a small portion touching the U.S. state of Maine...

 in Canada where the tides can rise fifty feet, or the now derelict village of Tide Mills
Tide Mills, East Sussex
Tide Mills is a derelict village in East Sussex, England. It lies about two kilometres south east of Newhaven and four kilometres north west of Seaford and is near both Bishopstone and East Blatchington.-The old village:...

 in the United Kingdom. A working example can be seen at Eling Tide Mill
Eling Tide Mill
Eling Tide Mill, situated on an artificial causeway in Eling in Hampshire, England, is one of only two remaining operating tide mills in the United Kingdom. The other is Woodbridge Tide Mill. Whilst a mill is mentioned in the Domesday Book of 1086, there is no evidence that there is any connection...

.

Other watermills can be set beneath large bridges where the flow of water between the stanchions is faster. At one point London bridge had so many water wheels beneath it that bargemen complained that passage through the bridge was impaired.

Watermills today

By the early 20th century, availability of cheap electrical energy made the watermill obsolete in developed countries although some smaller rural mills continued to operate commercially into the 1960s. A few historic mills such as the Newlin Mill
Newlin Mill Complex
The Newlin Mill Complex, a water powered gristmill on the west branch of Chester Creek near Concordville, Pennsylvania, USA, was built in 1704 by Nathaniel and Mary Newlin and operated commercially until 1941. During its three centuries of operation, the mill has been known as the Lower Mill, the...

 and Yates Mill
Yates Mill
Yates Mill is a fully restored, circa 1756 gristmill located five miles south of downtown Raleigh, North Carolina. It is the centerpiece of Historic Yates Mill County Park, located in central Wake County...

 (an example of an Oliver Evans
Oliver Evans
Oliver Evans was an American inventor. Evans was born in Newport, Delaware to a family of Welsh settlers. At the age of 14 he was apprenticed to a wheelwright....

 mill) (both USA) and The Darley Mill Centre
Darley, North Yorkshire
Darley is a straggling village in the middle of Nidderdale in the Harrogate district of North Yorkshire, England which has won many local and national 'Britain in Bloom' awards.Its westernmost end is Darley Head.- External links :*****...

 (Yorkshire, UK)) still operate for demonstration purposes to this day, or even maintain small-scale commercial production as at Daniels Mill, Shropshire
Daniels Mill, Shropshire
Daniels Mill is a working water mill used for milling flour, located near Bridgnorth in the English county of Shropshire. The mill has the largest cast iron waterwheel in England, spanning a 38-foot diameter....

 , Little Salkeld
Little Salkeld
Little Salkeld is a small village within the Eden district of Cumbria, England, a few miles to the north east of Penrith and within the parish of Hunsonby.-History:The manor at Little Salkeld was confirmed by King Edward I in 1292...

 and Redbournbury Mill
Redbournbury Mill
Redbournbury Mill, a water-driven flour mill, lies on the River Ver in the hamlet of Redbournbury between St Albans and Redbourn in the county of Hertfordshire, England....

 (All UK).

Some old mills are being upgraded with modern Hydropower
Hydropower
Hydropower, hydraulic power, hydrokinetic power or water power is power that is derived from the force or energy of falling water, which may be harnessed for useful purposes. Since ancient times, hydropower has been used for irrigation and the operation of various mechanical devices, such as...

 technology, for example those worked on by the South Somerset Hydropower Group
South Somerset Hydropower Group
The South Somerset Hydropower Group is a group of 10 owners of former watermills in the South Somerset area of England who are installing micro-hydro turbines for electricity generation. The Group was founded as a result of an initiative by South Somerset District Council, and was the first of...

 in the UK.

In some developing countries, watermills are still widely used for processing grain. For example, there are thought to be 25,000 operating in Nepal, and 200,000 in India. Many of these are still of the traditional style, but some have been upgraded by replacing wooden parts with better-designed metal ones to improve the efficiency. For example, the Centre for Rural Technology, Nepal upgraded 2,400 mills between 2003 and 2007.

Applications

  • Gristmill
    Gristmill
    The terms gristmill or grist mill can refer either to a building in which grain is ground into flour, or to the grinding mechanism itself.- Early history :...

    s, or corn mills, grind grain
    GRAIN
    GRAIN is a small international non-profit organisation that works to support small farmers and social movements in their struggles for community-controlled and biodiversity-based food systems. Our support takes the form of independent research and analysis, networking at local, regional and...

    s into flour
    Flour
    Flour is a powder which is made by grinding cereal grains, other seeds or roots . It is the main ingredient of bread, which is a staple food for many cultures, making the availability of adequate supplies of flour a major economic and political issue at various times throughout history...

    . These were undoubtedly the most common kind of mill.
  • Fulling or walk mills were used for a finishing process on woollen cloth.
  • Sawmill
    Sawmill
    A sawmill is a facility where logs are cut into boards.-Sawmill process:A sawmill's basic operation is much like those of hundreds of years ago; a log enters on one end and dimensional lumber exits on the other end....

    s cut timber
    Timber
    Timber may refer to:* Timber, a term common in the United Kingdom and Australia for wood materials * Timber, Oregon, an unincorporated community in the U.S...

     into lumber
    Lumber
    Lumber or timber is wood in any of its stages from felling through readiness for use as structural material for construction, or wood pulp for paper production....

    .
  • Bark mills ground bark
    Tanbark
    Tanbark is the bark of certain species of tree. It is traditionally used for tanning hides.The words "tanning", "tan," and "tawny" are derived from the Medieval Latin tannare, "to convert into leather."...

    , from oak or chestnut tree
    Tree
    A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...

    s to produce a coarse powder for use in tanneries
    Tanning
    Tanning is the making of leather from the skins of animals which does not easily decompose. Traditionally, tanning used tannin, an acidic chemical compound from which the tanning process draws its name . Coloring may occur during tanning...

    .
  • Spoke mills turned lumber
    Lumber
    Lumber or timber is wood in any of its stages from felling through readiness for use as structural material for construction, or wood pulp for paper production....

     into spokes for carriage
    Carriage
    A carriage is a wheeled vehicle for people, usually horse-drawn; litters and sedan chairs are excluded, since they are wheelless vehicles. The carriage is especially designed for private passenger use and for comfort or elegance, though some are also used to transport goods. It may be light,...

     wheels
    Wheel
    A wheel is a device that allows heavy objects to be moved easily through rotating on an axle through its center, facilitating movement or transportation while supporting a load, or performing labor in machines. Common examples found in transport applications. A wheel, together with an axle,...

    .
  • Cotton mill
    Cotton mill
    A cotton mill is a factory that houses spinning and weaving machinery. Typically built between 1775 and 1930, mills spun cotton which was an important product during the Industrial Revolution....

    s were driven by water. The power was used to card
    Carding
    Carding is a mechanical process that breaks up locks and unorganised clumps of fibre and then aligns the individual fibres so that they are more or less parallel with each other. The word is derived from the Latin carduus meaning teasel, as dried vegetable teasels were first used to comb the raw wool...

     the raw cotton, and then to drive the spinning mules and ring frames
    Water frame
    The water frame is the name given to the spinning frame, when water power is used to drive it. Both are credited to Richard Arkwright who patented the technology in 1768. It was based on an invention by Thomas Highs and the patent was later overturned...

    . Steam engine
    Stationary steam engine
    Stationary steam engines are fixed steam engines used for pumping or driving mills and factories, and for power generation. They are distinct from locomotive engines used on railways, traction engines for heavy steam haulage on roads, steam cars , agricultural engines used for ploughing or...

    s were initially used to increase the water flow to the wheel, then as the industrial revolution
    Industrial Revolution
    The Industrial Revolution was a period from the 18th to the 19th century where major changes in agriculture, manufacturing, mining, transportation, and technology had a profound effect on the social, economic and cultural conditions of the times...

     progressed, to directly drive the shafts.
  • Bobbin mills made wooden bobbins for the cotton
    Cotton
    Cotton is a soft, fluffy staple fiber that grows in a boll, or protective capsule, around the seeds of cotton plants of the genus Gossypium. The fiber is almost pure cellulose. The botanical purpose of cotton fiber is to aid in seed dispersal....

     and other textile industries.
  • Carpet mills for making carpets and rugs were sometimes water-powered.
  • Textile mills for spinning yarn or weaving cloth were sometimes water-powered.
  • Powder mill
    Powder mill
    The term powder mill is usually used for a mill that manufactures blackpowder, a type of gunpowder.A powder mill could be driven by wind or water power, and contained rollers for grinding the ingredients of gunpowder together, as well as presses and tumbling barrels and sieves for compacting,...

    s for making gunpowder
    Gunpowder
    Gunpowder, also known since in the late 19th century as black powder, was the first chemical explosive and the only one known until the mid 1800s. It is a mixture of sulfur, charcoal, and potassium nitrate - with the sulfur and charcoal acting as fuels, while the saltpeter works as an oxidizer...

     - black powder or smokeless powder
    Smokeless powder
    Smokeless powder is the name given to a number of propellants used in firearms and artillery which produce negligible smoke when fired, unlike the older gunpowder which they replaced...

     were usually water-powered.
  • Blast furnace
    Blast furnace
    A blast furnace is a type of metallurgical furnace used for smelting to produce industrial metals, generally iron.In a blast furnace, fuel and ore and flux are continuously supplied through the top of the furnace, while air is blown into the bottom of the chamber, so that the chemical reactions...

    s, finery forge
    Finery forge
    Iron tapped from the blast furnace is pig iron, and contains significant amounts of carbon and silicon. To produce malleable wrought iron, it needs to undergo a further process. In the early modern period, this was carried out in a finery forge....

    s, and tinplate works were, until the introduction of the steam engine, almost invariably water powered. Furnaces and Forges were sometimes called iron mills.
  • Blade mill
    Blade mill
    A blade mill was a variety of water mill used for sharpening newly fabricated blades, including scythes, swords, sickles, and knives.In the Sheffield area, they were known as cutlers wheels, scythesmiths wheels, etc. Examples are preserved in Abbeydale Industrial Hamlet...

    s were used for sharpening newly made blades.
  • Slitting mill
    Slitting mill
    The slitting mill was a watermill for slitting bars of iron into rods. The rods then were passed to nailers who made the rods into nails, by giving them a point and head....

    s were used for slitting bars of iron into rods, which were then made into nails.
  • Rolling mills shaped metal by passing it between rollers.
  • Lead was usually smelted in smeltmill
    Smeltmill
    Smeltmills were water-powered mills used to smelt lead or other metals.The older method of smelting lead on wind-blown bole hills began to be superseded by artificially-blown smelters. The first such furnace was built by Burchard Kranich at Makeney, Derbyshire in 1554, but produced less good lead...

    s prior to the introduction of the cupola (a reverberatory furnace
    Reverberatory furnace
    A reverberatory furnace is a metallurgical or process furnace that isolates the material being processed from contact with the fuel, but not from contact with combustion gases...

    ).
  • Paper mill
    Paper mill
    A paper mill is a factory devoted to making paper from vegetable fibres such as wood pulp, old rags and other ingredients using a Fourdrinier machine or other type of paper machine.- History :...

    s used water not only for motive power, but also required it in large quantities in the manufacturing process.
  • Stamp mill
    Stamp mill
    A stamp mill is a type of mill machine that crushes material by pounding rather than grinding, either for further processing or for extraction of metallic ores. Breaking material down is a type of unit operation....

    s for crushing ore
    Ore
    An ore is a type of rock that contains minerals with important elements including metals. The ores are extracted through mining; these are then refined to extract the valuable element....

    , usually from non-ferrous mines
  • Needle mills for scouring needles during manufacture were mostly water-powered (such as Forge Mill Needle Museum
    Forge Mill Needle Museum
    The Forge Mill Needle Museum in Redditch, Worcestershire, is a historic museum depicting Redditch's Industrial Heritage. Opened in 1983 by Queen Elizabeth II, it records how in Victorian times, Redditch was the international centre of the needle and fishing tackle industry and once produced 90% of...

    )
  • Oil mills for crushing oil seeds might be wind or water-powered

See also

  • List of watermills
  • Hydropower
    Hydropower
    Hydropower, hydraulic power, hydrokinetic power or water power is power that is derived from the force or energy of falling water, which may be harnessed for useful purposes. Since ancient times, hydropower has been used for irrigation and the operation of various mechanical devices, such as...

  • Micro hydro
    Micro hydro
    Micro hydro is a term used for hydroelectric power installations that typically produce up to 100 kW of electricity. These installations can provide power to an isolated home or small community, or are sometimes connected to electric power networks....

  • Millstone
    Millstone
    Millstones or mill stones are used in windmills and watermills, including tide mills, for grinding wheat or other grains.The type of stone most suitable for making millstones is a siliceous rock called burrstone , an open-textured, porous but tough, fine-grained sandstone, or a silicified,...

  • Molinology
    Molinology
    Molinology is the study of mills or other mechanical devices which use the kinetic energy of moving water or wind to power machines for such purposes as hammering, grinding, pumping, sawing, pressing or fulling. Muscle-powered mills are also considered to be part of the field...

  • The International Molinological Society
    The International Molinological Society
    The International Molinological Society has been active since 1965 and is the only organization dedicated to mills and molinology on a worldwide scale. It brings together more than six hundred members, mostly from Europe and the USA. TIMS is a non-profit organization with cultural and scientific...

  • Renewable Energy
    Renewable energy
    Renewable energy is energy which comes from natural resources such as sunlight, wind, rain, tides, and geothermal heat, which are renewable . About 16% of global final energy consumption comes from renewables, with 10% coming from traditional biomass, which is mainly used for heating, and 3.4% from...

  • Roman engineering
    Roman engineering
    Romans are famous for their advanced engineering accomplishments, although some of their own inventions were improvements on older ideas, concepts and inventions. Technology for bringing running water into cities was developed in the east, but transformed by the Romans into a technology...

  • Scoop wheel
    Scoop wheel
    right|thumb|Rim driven Scoop wheel of the [[Stretham Old Engine]], CambridgeshireA scoop wheel may be a pump or an excavator.-Scoop wheel pump:...

     - the exact opposite of a waterwheel
  • Sustainable living
    Sustainable living
    Sustainable living is a lifestyle that attempts to reduce an individual's or society's use of the Earth's natural resources and his/her own resources. Practitioners of sustainable living often attempt to reduce their carbon footprint by altering methods of transportation, energy consumption and diet...

  • Sutter's Mill
    Sutter's Mill
    Sutter's Mill was a sawmill owned by 19th century pioneer John Sutter in partnership with James W. Marshall. It was located in Coloma, California, at the bank of the South Fork American River...

  • Watermills in the United Kingdom
    Watermills in the United Kingdom
    The use of water power in Britain was at its peak just before the Industrial Revolution. The need for power was great and steam power had not yet become established. It is estimated that at this time there were well in excess of ten thousand watermills in the country...

  • Horse mill
    Horse mill
    A horse mill is a mill that uses a horse as the power source. Any milling process can be powered in this way, but the most frequent use of animal power in horse mills was for grinding grain and pumping water. Other animals used for powering mills include dogs, donkeys and oxen. Engines powered by...

  • Claverton Pumping Station
    Claverton Pumping Station
    Claverton Pumping Station in the village of Claverton, in the English county of Somerset, pumps water from the River Avon to the Kennet and Avon Canal using power from the flow of the River Avon. It is a grade II listed building....

     – a waterwheel-powered pumping station
  • Watermill of Veaux
    Watermill of Veaux
    "Moulin des Veaux" is a French watermill in Chavenon in the Allier départment in the Auvergne Region-History:Watermill of on the Aumance River . The Aumance River is a tributary of the Cher River. This mill is on the Cassini map...

  • Windmill
    Windmill
    A windmill is a machine which converts the energy of wind into rotational energy by means of vanes called sails or blades. Originally windmills were developed for milling grain for food production. In the course of history the windmill was adapted to many other industrial uses. An important...


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