Roman engineering - AbsoluteAstronomy.com

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....

are famous for their advanced engineering

Engineering

Engineering is the discipline, art, skill and profession of acquiring and applying scientific, mathematical, economic, social, and practical knowledge, in order to design and build structures, machines, devices, systems, materials and processes that safely realize improvements to the lives of...

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 inconceivable in Greece. The architecture used in Rome was strongly influenced by Greek

Architecture of Ancient Greece

The architecture of Ancient Greece is the architecture produced by the Greek-speaking people whose culture flourished on the Greek mainland and Peloponnesus, the Aegean Islands, and in colonies in Asia Minor and Italy for a period from about 900 BC until the 1st century AD, with the earliest...

and Etruscan

Etruscan civilization

Etruscan civilization is the modern English name given to a civilization of ancient Italy in the area corresponding roughly to Tuscany. The ancient Romans called its creators the Tusci or Etrusci...

sources. Roads were common at that time, but the Romans improved their design and perfected the construction to the extent that many of their roads are still in use today. Their accomplishments surpassed most other civilizations of their time, and after their time, and many of their structures have withstood the test of time to inspire others, especially during the Renaissance

Renaissance

The Renaissance was a cultural movement that spanned roughly the 14th to the 17th century, beginning in Italy in the Late Middle Ages and later spreading to the rest of Europe. The term is also used more loosely to refer to the historical era, but since the changes of the Renaissance were not...

. Moreover, their contributions were described in some detail by authors such as 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 ....

, Frontinus and 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...

, so there is a printed record of their many inventions and achievements.

Aqueducts

Three hundred million gallons of water were brought into Rome by 14 different aqueducts each day. Per capita water usage in ancient Rome matched that of modern-day cities like New York City or modern Rome. Most water was for public uses, such as baths

Thermae

In ancient Rome, thermae and balnea were facilities for bathing...

and sewers. The aqueducts could stretch from ten to sixty miles long, and typically descended from an elevation of one thousand feet above sea level at the source, to two hundred feet when they reached the reservoirs around the city. Roman engineers used inverted siphon

Siphon

The word siphon is sometimes used to refer to a wide variety of devices that involve the flow of liquids through tubes. But in the English language today, the word siphon usually refers to a tube in an inverted U shape which causes a liquid to flow uphill, above the surface of the reservoir,...

s to move water across a valley if they judged it impractical to build a raised aqueduct.

The Romans were among the first civilizations to harness the power of water. They built some of the first watermill

Watermill

A watermill is a structure that uses a water wheel or turbine to drive a mechanical process such as flour, lumber or textile production, or metal shaping .- History :...

s outside of Greece for grinding flour and spread the technology for constructing watermills throughout the Mediterranean region. A famous example occurs at Barbegal in southern France, where no fewer than 16 overshot mills built into the side of a hill were worked by a single aqueduct, the outlet from one feeding the mill below in a cascade. They were also skilled in mining, building aqueducts needed to supply equipment used in extracting metal ores, e.g. hydraulic mining

Hydraulic mining

Hydraulic mining, or hydraulicking, is a form of mining that uses high-pressure jets of water to dislodge rock material or move sediment. In the placer mining of gold or tin, the resulting water-sediment slurry is directed through sluice boxes to remove the gold.-Precursor - ground...

, and the building of reservoirs to hold the water needed at the minehead. It is known that they were also capable of building and operating mining equipment such as crushing mills and dewatering machines. Large diameter vertical wheels of Roman vintage, for raising water, have been excavated from the Rio Tinto

Rio Tinto Group

The Rio Tinto Group is a diversified, British-Australian, multinational mining and resources group with headquarters in London and Melbourne. The company was founded in 1873, when a multinational consortium of investors purchased a mine complex on the Rio Tinto river, in Huelva, Spain from the...

mines in Southwestern Spain. They were closely involved in exploiting 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...

resources such as those at Dolaucothi in south west Wales

Wales

Wales is a country that is part of the United Kingdom and the island of Great Britain, bordered by England to its east and the Atlantic Ocean and Irish Sea to its west. It has a population of three million, and a total area of 20,779 km²...

and in north-west Spain, a country where gold mining

Gold mining

Gold mining is the removal of gold from the ground. There are several techniques and processes by which gold may be extracted from the earth.-History:...

developed on a very large scale in the early part of the first century AD, such as at Las Medulas

Las Médulas

Las Médulas is a historical site near the town of Ponferrada in the region of El Bierzo , which used to be the most important gold mine in the Roman Empire...

Bridges

Roman bridges were among the first large and lasting bridges ever built. They were built with stone, employing the arch

Arch

An arch is a structure that spans a space and supports a load. Arches appeared as early as the 2nd millennium BC in Mesopotamian brick architecture and their systematic use started with the Ancient Romans who were the first to apply the technique to a wide range of structures.-Technical aspects:The...

as basic structure. Most utilized concrete as well.
Built in 142 BC

142 BC

Year 142 BC was a year of the pre-Julian Roman calendar. At the time it was known as the Year of the Consulship of Calvus and Servilianus...

, the Pons Aemilius

Pons Aemilius

The Pons Aemilius , today called Ponte Rotto, is the oldest Roman stone bridge in Rome, Italy. Preceded by a wooden version, it was rebuilt in stone in the 2nd century BC...

, later named Ponte Rotto (broken bridge) is the oldest Roman stone bridge in Rome, Italy. The biggest Roman bridge was Trajan's bridge

Trajan's bridge

Trajan's Bridge or Bridge of Apollodorus over the Danube was a Roman segmental arch bridge, the first to be built over the lower Danube. For more than a thousand years, it was the longest arch bridge in the world, in terms of both total and span length...

over the lower Danube, constructed by Apollodorus of Damascus

Apollodorus of Damascus

Apollodorus of Damascus was a Greek engineer, architect, designer and sculptor who flourished during the 2nd century AD, from Damascus, Roman Syria. He was a favourite of Trajan, for whom he constructed Trajan's Bridge over the Danube for the 105-106 campaign in Dacia. He also designed the Forum...

, which remained for over a millennium the longest bridge to have been built both in terms of overall and span length. They were normally at least 18 meters above the body of water.

An example of temporary military bridge construction are the two Caesar's Rhine bridges

Caesar's Rhine bridges

Caesar's Bridge across the Rhine, the first two bridges to cross the Rhine River, were built by Julius Caesar and his legionaries during the Gallic War in 55 BC and 53 BC, respectively...

Dams

The Romans built many dams

DAMS

Driot-Arnoux Motorsport is a racing team from France, involved in many areas of motorsports. DAMS was founded in 1988 by Jean-Paul Driot and former Formula One driver René Arnoux. It is headquartered near Le Mans, only 2 km from the Bugatti Circuit.- History :The year after its foundation,...

for water collection, such as the Subiaco

Subiaco, Italy

Subiaco is a town and comune in the Province of Rome, in Lazio, Italy, from Tivoli alongside the river Aniene. It is mainly renowned as a tourist and religious resort for its sacred grotto , in the St. Benedict's Abbey, and the other Abbey of St. Scholastica...

dams, two of which fed Anio Novus

Anio Novus

Anio Novus is an aqueduct of Rome. Together with the Aqua Claudia, it was begun by emperor Caligula in 38 AD and completed in 52 AD by Claudius, who dedicated them both on August 1.-Details:...

, the largest aqueduct supplying Rome. One of the Subiaco

Subiaco, Italy

dams was reputedly the highest ever found or inferred. They built 72 dams in Spain, such as those at Mérida

Mérida, Spain

Mérida is the capital of the autonomous community of Extremadura, western central Spain. It has a population of 57,127 . The Archaeological Ensemble of Mérida is a UNESCO World Heritage site since 1993.- Climate :...

, and many more are known across the empire. At one site, Montefurado in Galicia, they appear to have built a dam across the river Sil to expose alluvial gold deposits in the bed of the river. The site is near the spectacular Roman gold mine of Las Medulas

Las Médulas

Las Médulas is a historical site near the town of Ponferrada in the region of El Bierzo , which used to be the most important gold mine in the Roman Empire...

. Several earthen dams are known from Britain, including a well-preserved example from Roman Lanchester, Longovicium

Longovicium

Longovicium was an auxiliary fort on Dere Street, in the Roman province of Britannia Inferior. It is located just southwest of Lanchester in the English county of Durham, roughly to the west of the city of Durham and from Consett.-History:Longovicium was situated between the forts of...

, where it may have been used in industrial-scale smithing or smelting

Smelting

Smelting is a form of extractive metallurgy; its main use is to produce a metal from its ore. This includes iron extraction from iron ore, and copper extraction and other base metals from their ores...

, judging by the piles of slag found at this site in northern England. Tanks for holding water are also common along aqueduct systems, and numerous examples are known from just one site, the gold mines at Dolaucothi in west Wales

Wales

. Masonry dams were common in North Africa for providing a reliable water supply from the wadi

Wadi

Wadi is the Arabic term traditionally referring to a valley. In some cases, it may refer to a dry riverbed that contains water only during times of heavy rain or simply an intermittent stream.-Variant names:...

s behind many settlements.

Architecture

The buildings and architecture of Ancient Rome

Ancient Rome

Ancient Rome was a thriving civilization that grew on the Italian Peninsula as early as the 8th century BC. Located along the Mediterranean Sea and centered on the city of Rome, it expanded to one of the largest empires in the ancient world....

were impressive even by modern standards. The Circus Maximus

Circus Maximus

The Circus Maximus is an ancient Roman chariot racing stadium and mass entertainment venue located in Rome, Italy. Situated in the valley between the Aventine and Palatine hills, it was the first and largest stadium in ancient Rome and its later Empire...

, for example, was large enough to be used as a stadium. The Colosseum

Colosseum

The Colosseum, or the Coliseum, originally the Flavian Amphitheatre , is an elliptical amphitheatre in the centre of the city of Rome, Italy, the largest ever built in the Roman Empire...

also provides an example of Roman architecture at its finest. One of many stadiums built by the Romans, the Colosseum exhibits the arches and curves commonly associated with Roman buildings. The Pantheon

Pantheon, Rome

The Pantheon ,Rarely Pantheum. This appears in Pliny's Natural History in describing this edifice: Agrippae Pantheum decoravit Diogenes Atheniensis; in columnis templi eius Caryatides probantur inter pauca operum, sicut in fastigio posita signa, sed propter altitudinem loci minus celebrata.from ,...

in Rome still stands a monument and tomb, and the Baths of Diocletian

Baths of Diocletian

The Baths of Diocletian in Rome were the grandest of the public baths, or thermae built by successive emperors. Diocletian's Baths, dedicated in 306, were the largest and most sumptuous of the imperial baths. The baths were built between the years 298 AD and 306 AD...

and the Baths of Caracalla

Baths of Caracalla

The Baths of Caracalla in Rome, Italy were Roman public baths, or thermae, built in Rome between AD 212 and 216, during the reign of the Emperor Caracalla.- History :...

are remarkable for their state of preservation, the former still possessing intact dome

Dome

A dome is a structural element of architecture that resembles the hollow upper half of a sphere. Dome structures made of various materials have a long architectural lineage extending into prehistory....

s. Such massive public buildings were copied in numerous provincial capitals and towns across the empire, and the general principles behind their design and construction are described by 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 ....

writing at the turn of millennium in his monumental work De architectura
De architectura
' is a treatise on architecture written by the Roman architect Vitruvius and dedicated to his patron, the emperor Caesar Augustus, as a guide for building projects...

. The technology developed for the baths was especially impressive, especially the widespread use of the hypocaust

Hypocaust

A hypocaust was an ancient Roman system of underfloor heating, used to heat houses with hot air. The word derives from the Ancient Greek hypo meaning "under" and caust-, meaning "burnt"...

for one of the first types of central heating

Central heating

A central heating system provides warmth to the whole interior of a building from one point to multiple rooms. When combined with other systems in order to control the building climate, the whole system may be a HVAC system.Central heating differs from local heating in that the heat generation...

developed anywhere. That invention was used not just in the large public buildings, but spread to domestic buildings such as the many villa

Villa

A villa was originally an ancient Roman upper-class country house. Since its origins in the Roman villa, the idea and function of a villa have evolved considerably. After the fall of the Roman Republic, villas became small farming compounds, which were increasingly fortified in Late Antiquity,...

s which were built across the Empire.

Materials

The most common materials used were brick

Brick

A brick is a block of ceramic material used in masonry construction, usually laid using various kinds of mortar. It has been regarded as one of the longest lasting and strongest building materials used throughout history.-History:...

, stone

Dimension stone

Dimension stone is natural stone or rock that has been selected and fabricated to specific sizes or shapes. Color, texture and pattern, and surface finish of the stone are also normal requirements...

or masonry

Masonry

Masonry is the building of structures from individual units laid in and bound together by mortar; the term masonry can also refer to the units themselves. The common materials of masonry construction are brick, stone, marble, granite, travertine, limestone; concrete block, glass block, stucco, and...

, cement

Cement

In the most general sense of the word, a cement is a binder, a substance that sets and hardens independently, and can bind other materials together. The word "cement" traces to the Romans, who used the term opus caementicium to describe masonry resembling modern concrete that was made from crushed...

, concrete

Concrete

Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...

and 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...

. Brick came in many different shapes. Curved bricks were used to build columns, and triangular bricks were used to build walls.

Marble was mainly a decorative material. Caesar Augustus

Augustus

Augustus ;23 September 63 BC – 19 August AD 14) is considered the first emperor of the Roman Empire, which he ruled alone from 27 BC until his death in 14 AD.The dates of his rule are contemporary dates; Augustus lived under two calendars, the Roman Republican until 45 BC, and the Julian...

once boasted that he had turned Rome from a city of stone to a city of marble. The Romans had originally brought marble over from Greece, but later found their own quarries in northern Italy.

Cement was made of hydrated lime (calcium oxide) mixed with sand and water. The Romans discovered that substituting or supplementing the sand with a pozzolanic additive

Pozzolan

A pozzolan is a material which, when combined with calcium hydroxide, exhibits cementitious properties. Pozzolans are commonly used as an addition to Portland cement concrete mixtures to increase the long-term strength and other material properties of Portland cement concrete, and in some cases...

, such as volcanic ash, would produce a very hard cement, known as hydraulic mortar or hydraulic cement. They used it widely in structures such as buildings, public baths and aqueducts, ensuring their survival into the modern era.

Roads

Roman roads were constructed to be immune to floods and other environmental hazards. Many roads built by the Romans are still in use today.

There were several variations on a standard Roman road. Most of the higher quality roads were composed of five layers. The bottom layer, called pavimentum, was one inch thick and made of mortar. Above this were four strata of masonry. The layer directly above the pavimentum was called the statumen. It was one foot thick, and was made of stones bound together by cement or clay. Above that, there were the rudens, which were made of ten inches of rammed concrete. The next layer, the nucleus, was made of twelve to eighteen inches of successively laid and rolled layers of concrete. Summa crusta of silex or lava polygonal slabs, one to three feet in diameter and eight to twelve inches thick, were laid on top of the rudens. The final upper surface was made of concrete or well smoothed and fitted flint.

Generally, when a road encountered an obstacle, the Romans preferred to engineer a solution to the obstacle rather than redirecting the road around it. Bridges were constructed over all sizes of waterway, marshy ground called for the construction of raised causeways with firm foundations, and hills and outcroppings were frequently cut or tunneled through rather than avoided. The tunnels were made with square hard rock block.

Mining

The Romans were the first to exploit mineral deposits using advanced technology, especially the use of aqueducts to bring water from great distances to help operations at the pithead. Their technology is most visible at sites in Britain such as Dolaucothi where they exploited gold deposits with at least 5 long aqueducts tapping adjacent rivers and streams. They used the water to prospect for ore by unleashing a wave of water from a tank to scour away the soil and so reveal the bedrock with any veins exposed to sight. They used the same method (known as hushing

Hushing

Hushing is an ancient and historic mining method using a flood or torrent of water to reveal mineral veins. The method was applied in several ways, both in prospecting for ores, and for their exploitation. Mineral veins are often hidden below soil and sub-soil, which must be stripped away to...

) to remove waste rock, and then to quench hot rocks weakened by fire-setting

Fire-setting

Fire-setting is a method of mining used since prehistoric times up to the Middle Ages. Fires were set against a rock face to heat the stone, which was then doused with water...

. Such methods could be very effective in opencast mining, but fire-setting was very dangerous when used in underground workings. They were made redundant with the introduction of explosives, although hydraulic mining

Hydraulic mining

is still used on alluvial tin

Tin

Tin is a chemical element with the symbol Sn and atomic number 50. It is a main group metal in group 14 of the periodic table. Tin shows chemical similarity to both neighboring group 14 elements, germanium and lead and has two possible oxidation states, +2 and the slightly more stable +4...

ores. They were also used to produce a controlled supply to wash the crushed ore. It is highly likely that they also developed 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....

s to crush hard ore, which could be washed to collect the heavy gold dust.

At alluvial mines, they applied their hydraulic mining

Hydraulic mining

methods on a vast scale, such as Las Medulas

Las Médulas

Las Médulas is a historical site near the town of Ponferrada in the region of El Bierzo , which used to be the most important gold mine in the Roman Empire...

in north-west Spain. Traces of tanks and aqueducts can be found at many other early Roman mines. The methods are described in great detail by Pliny the Elder

Pliny the Elder

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...

. He also described deep mining underground, and mentions the need to dewater the workings using reverse overshot water-wheel

Reverse overshot water-wheel

Frequently used in mines and probably elsewhere , the reverse overshot water wheel was a Roman innovation to help remove water from the lowest levels of underground workings. It is described by Vitruvius in his work De Architectura published circa 25 BC...

s, and actual examples have been found in many Roman mines exposed during later mining attempts. The copper mines at Rio Tinto were one source of such artifacts, where a set of 16 was found in the 1920s. They also used Archimedean screws to remove water in a similar way.

Military engineering

Engineering was also institutionally ingrained in the Roman military, who constructed forts, camps, bridges, roads, ramps, pallisades, and siege equipment amongst others. One of the most notable examples of military bridge-building in the Roman Empire was Julius Caesar's bridge over the Rhine River. This bridge was completed in only ten days by a dedicated team of engineers. Their exploits in the Dacian wars under Trajan

Trajan

Trajan , was Roman Emperor from 98 to 117 AD. Born into a non-patrician family in the province of Hispania Baetica, in Spain Trajan rose to prominence during the reign of emperor Domitian. Serving as a legatus legionis in Hispania Tarraconensis, in Spain, in 89 Trajan supported the emperor against...

in the early 2nd century AD are recorded on Trajan's column

Trajan's Column

Trajan's Column is a Roman triumphal column in Rome, Italy, which commemorates Roman emperor Trajan's victory in the Dacian Wars. It was probably constructed under the supervision of the architect Apollodorus of Damascus at the order of the Roman Senate. It is located in Trajan's Forum, built near...

in Rome. The army was also closely involved in gold mining

Gold mining

Gold mining is the removal of gold from the ground. There are several techniques and processes by which gold may be extracted from the earth.-History:...

and probably built the extensive complex of 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...

s and cistern

Cistern

A cistern is a waterproof receptacle for holding liquids, usually water. Cisterns are often built to catch and store rainwater. Cisterns are distinguished from wells by their waterproof linings...

s at the Roman gold mine of Dolaucothi in Wales

Wales

shortly after conquest of the region in 75 AD.

Power technology

Water wheel technology was developed to a high level during the Roman period, a fact attested by 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 ....

and Pliny the Elder

Pliny the Elder

in De Architectura

De architectura

' is a treatise on architecture written by the Roman architect Vitruvius and dedicated to his patron, the emperor Caesar Augustus, as a guide for building projects...

and Naturalis Historia

Naturalis Historia

respectively. The largest complex of water wheels existed at Barbegal near Arles

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....

, where the site was fed by a channel from the main aqueduct feeding the town. It is estimated that the site comprised 16 separate overshot water wheels arranged in two parallel lines down the hillside. The outflow from one wheel became the input to the next one down in the sequence.
Twelve kilometers north of Arles, at Barbegal, near Fontvieille

Fontvieille

Fontvieille may refer to:*Fontvieille, Bouches-du-Rhône, a commune in the French département of Bouches-du-Rhône*Fontvieille, Monaco, a community within Monaco consisting of land reclaimed from the Mediterranean Sea...

, where the aqueduct arrived at a steep hill, the aqueduct fed a series of parallel 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...

s to power a flourmill. 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. 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. 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 at that time.
The Hierapolis sawmill

Hierapolis sawmill

The Hierapolis sawmill was a Roman water-powered stone sawmill at Hierapolis, Asia Minor . Dating to the second half of the 3rd century AD, the sawmill is the earliest known machine to combine a crank with a connecting rod....

was a Roman water-powered stone saw mill at Hierapolis

Hierapolis

Hierapolis was the ancient Greco-Roman city which sat on top of hot springs located in south western Turkey near Denizli....

, 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...

(modern-day Turkey

Turkey

Turkey , known officially as the Republic of Turkey , is a Eurasian country located in Western Asia and in East Thrace in Southeastern Europe...

). Dating to the second half of the 3rd century AD, the 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....

is the earliest known machine to combine 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...

with a 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....

.

The watermill

Watermill

A watermill is a structure that uses a water wheel or turbine to drive a mechanical process such as flour, lumber or textile production, or metal shaping .- History :...

is shown on a raised relief

Relief

Relief is a sculptural technique. The term relief is from the Latin verb levo, to raise. To create a sculpture in relief is thus to give the impression that the sculpted material has been raised above the background plane...

on the sarcophagus

Sarcophagus

A sarcophagus is a funeral receptacle for a corpse, most commonly carved or cut from stone. The word "sarcophagus" comes from the Greek σαρξ sarx meaning "flesh", and φαγειν phagein meaning "to eat", hence sarkophagus means "flesh-eating"; from the phrase lithos sarkophagos...

of Marcus Aurelius Ammianos, a local miller

Miller

A miller usually refers to a person who operates a mill, a machine to grind a cereal crop to make flour. Milling is among the oldest of human occupations. "Miller", "Milne" and other variants are common surnames, as are their equivalents in other languages around the world...

. A waterwheel fed by a 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...

is shown powering two frame saw

Frame saw

Frame saw sometimes refers to a woodworker's bow saw.A frame saw is a type of rip saw. It consists of a relatively narrow and flexible blade held under tension within a rectangular frame...

s via a gear train

Gear train

A gear train is formed by mounting gears on a frame so that the teeth of the gears engage. Gear teeth are designed to ensure the pitch circles of engaging gears roll on each other without slipping, this provides a smooth transmission of rotation from one gear to the next.The transmission of...

cutting rectangular blocks.

Further crank and connecting rod mechanisms, without gear train, are archaeologically attested for the 6th century AD water-powered stone sawmills at Gerasa, 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...

, 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...

, Turkey. Literary references to water-powered marble

Marble

saws in Trier

Trier

Trier, historically called in English Treves is a city in Germany on the banks of the Moselle. It is the oldest city in Germany, founded in or before 16 BC....

, 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...

' late 4th century AD poem Mosella. They attest a diversified use of water-power in many parts of the Roman Empire

Roman Empire

.

A complex of mills also 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...

in 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...

fed by the Aqua Traiana

Aqua Traiana

thumb|240px|Route of Aqua Traiana shown in red.thumb|240px|Route of Aqua Traiana within ancient Rome.The Aqua Traiana was a 1st-century Roman acqueduct built by Emperor Trajan and inaugurated on 24 June 109 AD...

. 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....

were carried up the hill apparently to include the water mills used to grind grain towards providing bread

Bread

Bread is a staple food prepared by cooking a dough of flour and water and often additional ingredients. Doughs are usually baked, but in some cuisines breads are steamed , fried , or baked on an unoiled frying pan . It may be leavened or unleavened...

flour

Flour

for the city. The mill was thus probably built at the same time as or before the walls were built by the 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...

(reigned 270-275 AD). The mills were supplied from an aqueduct, where it plunged down a steep hill. The site thus resembles 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"...

, although excavations in the late 1990s suggest that they may have been undershot rather than overshot in design. The mills were in use in 537 AD when the Goths

Goths

The Goths were an East Germanic tribe of Scandinavian origin whose two branches, the Visigoths and the Ostrogoths, played an important role in the fall of the Roman Empire and the emergence of Medieval Europe....

besieging the city cut off their water supply. However they were subsequently restored and may have remained in operation until at least the time of Pope Gregory IV

Pope Gregory IV

Pope Gregory IV was chosen to succeed Valentine in December 827, on which occasion he recognized the supremacy of the Frankish emperor Louis the Pious in the most unequivocal manner....

(827-44).

Many other sites are reported from across the Roman Empire

Roman Empire

, although many remain unexcavated.

Aqueducts

Bridges

Dams

Architecture

Materials

Roads

Mining

Military engineering

Power technology

See also