Millstone

The origins of an industry Often referred to as the "oldest industry", the use of the millstone is inextricably linked to human history. Integrated into food processes since the Upper Palaeolithic, its use remained constant until the end of the 19th century, when it was gradually replaced by a new type of metal tool. However, it can still be seen in rural domestic installations, such as in India, where 300 million women used hand mills daily to produce flour in 2002. The earliest evidence for stones used to grind food is found in northern Australia, at the Madjedbebe rock shelter in Arnhem Land, dating back around 60,000 years. Grinding stones or grindstones, as they were called, were used by the Aboriginal peoples across the continent and islands, and they were traded in areas where suitable sandstone was not available in abundance. Different stones were adapted for grinding different things and varied according to location. One important use was for foods, in particular to grind seeds to make bread, but stones were also adapted for grinding specific types of starchy nuts, ochres for artwork, plant fibres for string, or plants for use in bush medicine, and are still used today. The Australian grindstones usually comprise a large flat sandstone rock (for its abrasive qualities), used with a top stone, known as a "muller", "pounder", or pestle. The Aboriginal peoples of the present state of Victoria used grinding stones to crush roots, bulbs, tubers, and berries, as well as insects, small mammals, and reptiles before cooking them. In Ancient history site (Plomeur) Careful examination of Paleolithic grinders (pebbles, wheels, mortar and pestle, etc.) enables us to determine the nature of the action exerted on the material and the gesture performed; the function of the tool can then be specified, as well as the activity in which it participated. Neanderthal people were already using rudimentary tools to crush various substances, as attested by the presence of rudimentary grinders at the end of the Mousterian and millstones in the Châtelperronian. From the Aurignacian period onwards (around 38,000 years ago), Cro-Magnon man regularly used millstones, elongated grinders, and circular wheels. From the Gravettian period onwards (circa 29,000 years), this equipment became more diversified, with the appearance of new types of tools such as millstones and pestle grinders. At the end of the Palaeolithic, millstones from Wadi Kubbaniya (Middle East, 19,000 B.C.) were involved in dietary processes and associated with residues of tuberous plants, which were known to require grinding before consumption, either to extract their toxins (Cyperus rotundus, nutsedge), or to remove the fibrous texture that would make them indigestible (Scirpus maritimus). The rhizomes of ferns and the peel of the fruit of the doum palm, also found on this site, benefit from being ground to improve their nutritional qualities; they thus complemented the meat diet of hunter-gatherers. Grinding barley or oat seeds was practiced at the end of the Upper Palaeolithic (Franchthi) or the Kebarian (Ohalo II, 19,000 BC). As tools improved, the material was increasingly finely ground, but only when it became a real powder could we speak of grinding. Thus, the men of the European Upper Paleolithic were already dissociating grinding and milling, as attested by the appearance at this time of the first grinding slabs used with grinders or millstones. While there is no evidence of the milling of wild cereals in the early Upper Paleolithic, at least in Europe, there is no reason not to believe that other plant matter (acorns, nuts, hazelnuts, etc.) and animal matter (fat) were already being ground into paste before cooking. Similarly, it's likely that millstones were being used at this time for technical purposes, to crush mineral substances (dyes) and certain plant or animal fibers for technical use. (5500 - 5000 B.C.), Xinzheng In the Mesolithic and Neolithic eras, with the domestication of plants, much larger, fully formed grinding, pounding, and milling equipment appeared. From the Natufian onwards, several types of millstones can be found side by side, such as the deep "trough-shaped" millstone or the flat millstone, indicating a specialization of their function. In the Near East, the pestle-grinder began to be developed in the Kebarian and Natufian periods. It gradually evolved into the heavy, generally wooden, thrown pestle. This type of equipment is still used today in many regions, such as in Ethiopia for milling millet. The appearance of flat, elongated millstones in the Natoufian period (Abu Hureïra on the Euphrates) dates back to the 9th millennium BC. They feature larger active surfaces and mark the emergence of a new gesture, that of grinding from front to back, with both hands, which implies a new posture for the body, kneeling in front of the millstone. The appearance of large, asymmetrical, shaped millstones (Mureybet, Sheikh Hassan, circa 10,000 BP) led to the "saddle-shaped" millstones still known today as the metate. In India, millstone (Chakki) were used to grind grains and spices. These consist of a stationary stone cylinder upon which a smaller stone cylinder rotates. Smaller ones, for household use, were operated by two people. Larger ones, for community or commercial use, used livestock to rotate the upper cylinder. Today a majority of the stone flour mills (Atta Chakki) are equipped with lower stone rotating and upper stone stationary millstones also called Shikhar Emery Stones which are made from abrasive emery grains and grits, with a binding agent similar to Sorel Cement. These stones are made from two types of emery abrasives - Natural Jaspar Red Emery or Synthetic Calcined Bauxite Black Emery. . The monument is made from millstones that the villagers hid and used in secret, as the Soviet authorities had prohibited their use during the famine.|leftIn Korea, there were three different millstones, each made from different materials, serving other purposes, such as threshing, grinding, and producing starch. Generally, the handle of a millstone in Korea was made from an ash tree, the process for making a handle from the ash tree was known as "Mulpure-namu". To ensure that everything is "all right" with the creation of a millstone, a mason within ancient Korea offered food and alcohol in a ritual. Millstones were introduced to Britain by the Romans during the 1st century AD and were widely used there from the 3rd century AD onwards. In 1932–1933 in Ukraine, during the man-made famine known as Holodomor, the Soviet authorities prohibited the use of millstones, claiming that a millstone is a "mechanism for enrichment" (which was a negative term in Soviet communist ideology). This forced Ukrainian villagers to hide their manually operated millstones and use them secretly during the famine. In response, Soviet authorities regularly searched villages for "illegal" millstones and destroyed them. In 2007, the people of Victorivka village in Cherkasy Oblast built a monument using the millstones they had managed to hide and save from the Soviet plunder during the Holodomor. == Different techniques: grinding, crushing, milling ==

The preparation of vegetable products (roots, tubers, almonds, leaves, etc.), animal products (marrow, tendons, etc.), or mineral products (ochre) by grinding or milling, for consumption or technical use, has existed for several dozen millennia. Unlike crushing, in which a hard envelope such as a shell or bone is broken open to recover its contents, in this case, the aim is to reduce a much softer material to a powder or paste. Depending on the place and time, millstones were used for "dry" grinding: in the manufacture of flour, sugar, or spices, but also for the preparation of kaolinite, cement, phosphate, lime, enamel, fertilizer, and other minerals. The milling operation can also be carried out "wet", as in the case of durum wheat semolina, nixtamal, or the grinding of mustard seeds. During preparation, some raw materials produce a naturally fluid paste, as in olive crushing or cocoa grinding. In his typology of percussion, André Leroi-Gourhan defines several families of gestures, three of which are essential for the preparation of raw materials: • Crushing gestures involve vertical percussion using a heavy, elongated object in the manner of the African pestle. This gesture is also used by the trip hammer to make paper pulp, or in forging; • Milling gestures, using percussion, which are performed in a circular, disordered, or back-and-forth motion on a millstone; • Grinding gestures, in which the movements are roughly circular and occasionally vertical, thus combining a thrown percussion and a percussion posed, are qualified here as diffuse. This is the case with the contemporary mortar-pestle system. File:Pounding_millet_MS0818.jpg|Pilon: Vertical percussive crushing File:RICE_POLISHING_BY_FOOT_POWER.jpg|Crushing by hammering File:Aboriginal_grinding_stones.jpg|Monolithic millstone with knurled wheel: percussive milling with uncoordinated movements File:P1010979mod.jpg|Peruvian Stone Batán (sandstone): Percussive milling File:Black_peppercorns_with_mortar_and_pestle.jpg|Mortar and pestle: Grinding by diffused percussive impact and diffused percussive application == Milling systems ==

Until the invention of the watermill, mills operated using "strength-powered", i.e. the force of animals or people. The metate The metate is a nether millstone for domestic use, for grinding corn. It has been used for several thousand years (around 3000 BC) in the cultural area of Mesoamerica, and its name comes from the Nahuatl "metatl". From 1920 onwards, electric mills appeared in the countryside, owned by municipalities, cooperatives or private individuals. However, still in use today, nether millstones are still part of Mexico's rural heritage. File:Metate_Maya.jpg|Mayan dish depicting the use of a metate to grind cocoa beans. Chocolate Museum, Bruges. File:Metate_et_mano.jpg|Metate and mano from the Mayan period. Chocolate Museum, Bruges. File:Metate_Costa_Rica.jpg|Costa Rican funeral metate. Chocolate Museum, Bruges. File:Tortilleras_aztecas.jpg|Aztec mother teaching her daughter to make tortillas. Codex Mendoza. File:Tortilleras_Nebel.jpg|Las Tortilleras (The Tortilla Makers). Hand-colored lithograph, Mexico, early 19th century The Olynthus mill The town of Olynthus was destroyed in 348 BC by Philip II of Macedonia, and the name "Olynthus millstone, Olynthus grinder, Olynthus mill" has come to be attached to this type of mill, which represents a genuine technical revolution. In 1917, the Greek Konstantinos Kourouniotis elucidated the workings of the hopper millstone, which played an important role in ancient Greece. In the Olynthus mill, the nether millstone(4) is rectangular, resting on a table (5); it measures between 0.42 m and 0.65 m in length, 0.36 m to 0.54 m in width and 0.08 to 0.25 m in thickness. The grinder, which forms the upper millstone (common millstone (3)), is usually rectangular, sometimes oval, with a central hopper parallel to the long sides, designed to receive the grain to be ground. The mill is capped by a horizontal axle attached to a pivot (1) on one side of the table, the other end being operated by a worker who moves the lever (2) back and forth horizontally. The Olynthus mill thus shows the beginnings of mechanization, with millers now standing on their feet, making work easier. This type of mill certainly appeared as early as the beginning of the 5th century BC. Its use was widespread throughout the Greek civilization in the 4th century B.C., from Macedonia to the Peloponnese, and was adopted as far afield as the islands of Anatolia, Egypt, and modern-day Syria. It continued into the 1st century B.C., and sometimes even later, as the excavations at the Agora in Athens suggest. The importance of this mill type for the Greek world was confirmed by the discovery, in 1967, of 22 hopper mills in the cargo of a ship wrecked off Kyrenia, dated to the end of the 4th century BC. Increasing demand undoubtedly led to standardization in manufacturing and specialization of production centers. For example, flat Argolidian millstones, made of andesite and rhyolite, were produced from local quarries (Isthmus of Corinth, Saronic Gulf), while grinders came from more distant quarries (islands of Nysiros, Milos). point out that these millstones pre-date the earliest known examples of circular grain mills. So it was probably through oil production that the first rotary crushing machine was introduced. Cereals and other fruits and seeds followed. The oldest rotating millstone are thought to have originated in Spain 2,500 years ago(600 BC - 400 BC). It seems that the rotating millstone spread at the end of the 5th century BC from Spain, André Leroi-Gourhan states that "the transformation of rectilinear reciprocating motion into circular-continuous motion leads to another form of milling". Some authors do not agree on its geographical origin, located for some "towards Carthage and the Syrian-Egyptian region", "simultaneously in Spain and England" for others, and even though it was found in China in the 1st century BC. The Pompeian mill or "blood" mill With a diameter limited to the reach of an arm's movement, i.e. 40 to 70 cm, the hand mill could only produce a limited quantity of flour and was therefore essentially reserved for domestic use. By increasing the diameter and, above all, the height of the meta (nether millstone) and the catillus (runner millstone), the Romans were able to overcome this constraint with the animal-drawn Pompeian mill, also known as the "blood" mill. In this mill, the nether millstone is conical at the top and the runner millstone looks like an hourglass, with its lower half covering the conical top of the nether millstone. The upper part of the runner millstone acts as a funnel, and a slight gap is maintained between the two millstones. The running wheel pivots around a wooden axle embedded in the standing wheel, and it is thanks to its suspension on this axle that the gap between the two wheels is ensured. This type of millstone could be powered either by two or four men, or by animal rides, hence its name mola asinaria, literally "donkey mill". An example of this type of millstone can be found as early as the Classical era, used to grind ore in the Laurion mines, although it did not overtake the less efficient reciprocating millstone. Despite its qualities, it didn't really spread throughout the Roman world until later. Bakery in Pompeii. File:Carl_Bloch_-_Samson_and_the_Philistines_-_Google_Art_Project.jpg|Samson, prisoner of the Philistines, turns the millstone in prison, Carl Bloch (1863) The Roman trapetum The Hellenistic period also saw the appearance of the olive crusher, which the Romans called the trapetum. Legend has it that it was invented by Aristaeus, and excavations at Olynthus have revealed examples dating back to the 5th century BC. The resultant pulp could then be subjected to the action of a press to collect the oil. Millstones of southern Morocco by hand A melting pot of African, Eastern and Mediterranean civilizations, Morocco has preserved tools and techniques from different eras. The Volubilis site, located in Mauritania Tingitana (northeastern Morocco), features grain and olive mills from the Roman period (1st century-2nd century). These mills consist of a truncated cone-shaped standing millstone and a convex grinding ring to which the wooden machinery is connected, apparently operated without the aid of animal power. In this arrangement, the grinding ring is fitted onto the lying millstone. The Volubilitan olive millstone differs from the grain millstone by having oblique striations on the truncated surface of the lying millstone and on the inside of the grinding ring. Columella asserts that, to extract the oil, the millstones (molae) are more useful than the crusher (trapetum), as they can be lowered or raised according to the size of the fruit, so as to avoid crushing the stone. A second type of olive mill can be found on the same site, and consists of a monolithic vat on which a fluted drum turns around a vertical mast like the section of a column. This type of mill is more common and can be found on many sites, even in recent times. File:Volubilis1.11.JPG|Giant olive wheel - Volubilis File:Volubilis1.20.JPG|Grinder ring - Volubilis File:Presse_olive_Volubilis.jpg|Olive mill with grinding ring - Volubilis File:Volubilis1.1.JPG|Trituration mill with upright millstone - Volubilis The argan tree is a woodland species endemic to southwest Morocco. The technical environment of the argan mill covers its range. It's a stone hand mill used to grind roasted kernels and almonds. It stands out from the grain mill thanks to the truncated cone shape and greater height of its runner millstone (agurf wuflla), as well as the presence of a spout (abajjr or tilst) and a pouring spout (ils) on the nether millstone (agurf u wadday). At the center of the nether millstone is a short pivot (tamnrut) made of argan wood, around which the upper millstone rotates, pierced by an eyelet (tit n tzrgt) into which one or two handfuls of kernels are inserted. The circular movement is interrupted to remove the kernels after the millstone has been lifted. The whole unit can be raised on stones welded together in a "bakehouse"-style architecture, allowing embers or argan shells to warm the unit, thus facilitating grinding in winter. which praised the advantages of its site in order to retain its privileges, states that it possesses "thanks to the slope of the waters flowing through it, a large number of watermills". At the beginning of the Christian era, the watermill was still a novelty in the western Mediterranean, and Vitruvius classed it with irrigation machines. This type of mill proved ill-suited to the design of Pompeian millstones. In Caligula's time, "blood" mills were still dominant, as Apuleius describes. Over the course of the 1st and 2nd centuries, the watermill slowly spread to a wide variety of provinces: Brittany, Gaul, and Africa, where the rotary millstone was often more widespread than the Pompeian mill. Over the course of the 4th century, the watermill slowly replaced the "blood" mill in Rome itself, becoming the predominant mill in the 2nd century. While there were some spectacular achievements in cities, such as the Barbegal mill in Arles, the watermill seems to have spread more slowly to rural villas, as Palladius indicates. points out that medieval millstones were always monolithic, that black basalt stones were still monolithic in later centuries, and that white stones remained so until the 18th century. However, "gisantes" were sometimes made up of several irregularly shaped pieces. These were bound in plaster, encased in an iron or wooden casing, and sometimes placed on a bed of cemented bricks. In fact, the invention of millstones made of pieces, i.e. an assembly of several stones or tiles, remains difficult to date precisely. In the 15th century, the river trade passing through Paris was strictly controlled by the Hanseatic League of water merchants; "French companies" had to inform the clerks of the names of their partners, the city of destination, and the nature and value of the cargo. Thus, on May 3, 1452, a Rouen merchant named Robert Le Cornu declared that he was bringing to Normandy one or more boats loaded with 35 millstones, 5 blinkers, 100 carreaux and a tombstone. Various texts provide clues to the manufacture of millstones in the 17th century. On March 10, 1647, Jacques Vinault "sold 3 rounds of grinding stone" to Pierre Bailly. On March 26, 1652, another text evokes the difficulties of a millstone assembly site, with a "lack of wood to cook the plastre quy is not in sufficient quantity to plastrer and put in the places where it is necessary, joinct aussy that there is stone to suffice to make the millstones". On July 7, 1680, Sr Delugré "made a deal with Claude Duvau and Jullien Boullmer, stone molders [...] to supply them with 2 molds of molding stone and plaster to make the millstones [...] made and perfect to make flour". According to Dorothée Kleinmann, "economic milling" and its improvements really took off at the end of the 18th century. This led to the development of stone quarrying and millstone production in new regions such as Cinq-Mars-la-Pile and Domme, where "millstones are always formed by joining several pieces together; there are no blocks large enough to make masses from a single piece". In these locations, it seems that at the beginning of the eighteenth century, millstone was not yet quarried, preferring to salvage scattered blocks from woods, fields and vineyards, which sometimes considerably increased their value. Once the millstone blocks have been transported to the site and "peeled", the manufacturer selects the stones required for the millstone. The different pieces are classified according to their quality, taking into account hardness, grain, porosity, and color. At this stage, it is also necessary to take into account the milling system used in the country of dispatch, and the type of wheat produced in the region. Once the choice has been made, production begins with the center or "boitard", which is usually made in one piece. This must be very solid, especially for the current millstone, as it is at this level that the casing on which the millstone is suspended is fixed. Around the boitard, the tiles are arranged and fixed with plaster or cement, and chiseled to fit together sufficiently. A wheel of this type is generally made up of two to six quarters. "When the job is done and the blocks match, the worker adjusts them by cementing them with Portland cement, sometimes with a paste of Spanish white and oil that hardens with age, and clamps the whole with iron hoops". On the other side of the working surface, the back of the millstone, or "counter-molding", is surrounded by a strip of sheet metal serving as temporary formwork. To give the millstone the necessary weight and thickness, it is reloaded with small stones embedded in fine concrete, into which are inserted cast-iron balancing boxes, which may contain lead if necessary. Edge mill Horizontal use of the millstone is generally associated with milling. When the millstone is "upright", i.e. on its edge, it is used for grinding, crushing, or milling operations. In this configuration, the nether millstone is fixed by its eyebolt to a vertical mast located centrally on the nether millstone which acts as a pivot. Depending on the size of the installation, and to maintain the verticality of the mast, its upper part may be attached to a beam overhanging the mill. The current millstone is rotated either " by means of force", or more often, in a riding hall. In this way, the mill is driven by a double movement, turning on itself while pivoting around the mast, as in the Roman trapetum. In this type of device, the millstone is monolithic or made up of a paved or even masonry surface. Depending on the product to be processed, the millstone may be slightly concave, with a rim around the periphery to avoid dispersing the crushed material. File:Mošćenice029.jpg|Olive mill - The spar through the eyelet is held in place by a dowel and is used to turn the current millstone. File:High Atlas-The olive grinding mill (js).jpg|Olive mill. High Atlas File:Tou d'preinseu, Jèrri.jpg|"Apple lathe" driven by a horse. Ring-shaped trough serving as a lying millstone. The Elms, Jersey File:Chocolaterie-nestlé-broc mélangeur fève de cacao-ancien-3.jpg|Old Millstone equipped with windrow ploughs, used to grind cocoa beans File:Agris1.1.JPG|Millstone and riding hall - Agris (Charente) File:Crocq08.JPG|Millstone and oil press - Crocq (Creuse) File:Museodellolivo1.JPG|Olive mill with conical millstones (Spain) == Materials ==

approx. 4 cm In common language, "millstone" refers to any type of rock that may have been used in a mill, whereas in the geological sense, true "millstone" is defined as a siliceous accident in a sedimentary basin. The type of stone most suitable for making millstones is a siliceous rock called burrstone (or buhrstone), an open-textured, porous but tough, fine-grained sandstone, or a silicified, fossiliferous limestone. In some sandstones, the cement is calcareous. On a historical scale, it seems that most types of rock have been used in milling. Among the sedimentary rocks of potential use are limestone and sandstone. The latter soon emerged as the stones of choice, with porosities that make them easy to shape and extraction that can be facilitated by bedding between clay interbeds. It wasn't until the 15th century that millstones stricto sensu began to be quarried, a practice that became widespread in the 18th century. Deep-lying magmatic rocks, such as granite, are widespread, but were ultimately little used for millstone manufacture, probably due to their low porosity and the presence of black mica, which rapidly alters to form iron oxides. Basalt was widely used in Germany (Eifel), but is not widespread in France, with the exception of the Évenos volcano in Provence; other examples include the basalt millstones of the Agde volcano, and those of the Sainte Magdeleine volcano at La Môle, not far from Cogolin. Limestones are generally porous, with medium to low compressive strengths, so "classic" limestones seem to have been quickly abandoned in favor of better stones. Although very fine-grained, limestone polishes very quickly and needs to be re-cut frequently to keep the stones rough. Some sandstone limestones (Saint-Julien-des-Molières limestone) can have very good compressive strength (over 100 MPa). Sandstone rocks (sandstones and microconglomerates up to 1 cm) are the preferred material for millstones. Analysis of production sites shows that they can be limestone-cemented sandstones, silica-cemented sandstones, or even slightly metamorphosed sandstones. Millstones used in Britain were of several types: • Derbyshire Peak stones of grey Millstone Grit, cut from one piece, used for grinding barley; It was necessary to balance the completed runner stone with lead weights applied to the lighter side. In Europe, a further type of millstone was used. These were uncommon in Britain, but not unknown: • Cullen stones (stones from Cologne), a form of black lava quarried in the Rhine Valley at Mayen near Cologne, Germany. • Lava stones from Orvieto (Italy), Mount Etna and Hyblaean Mounts (Sicily), and Pantelleria island, were used by the Romans. ==Patterning==

The surface of a millstone is divided by deep grooves called furrows into separate flat areas called lands. Spreading away from the furrows are smaller grooves called feathering or cracking. The grooves provide a cutting edge and help to channel the ground flour out from the stones. The furrows and lands are arranged in repeating patterns called harps. A typical millstone will have six, eight or ten harps. The pattern of harps is repeated on the face of each stone, when they are laid face to face the patterns mesh in a kind of "scissoring" motion creating the cutting or grinding function of the stones. When in regular use stones need to be dressed periodically, that is, re-cut to keep the cutting surfaces sharp. The major challenge is to limit the heat generated by the pressure of the millstones on the ground flour. In addition to denaturing the flour (browning), this overheating, and any sparks generated by the rubbing of the stones, could cause an explosion in the mill, whose atmosphere is charged with fine flour particles. A complex system of spokes had to be devised to ventilate the gap between the millstones and, at the same time, progressively push the material from the eyelet to the peripheral rabbet. Wheat millstones have long been used to grind cereals in a single pass. We had to find the best way of extracting the flour and cleaning the bran, ensuring that it was unbroken and free of flour. Millstones need to be evenly balanced, and achieving the correct separation of the stones is crucial to producing good quality flour. The experienced miller will be able to adjust their separation very accurately. For the manufacture of the millstone, the customer had to specify the diameter, the size of the eye and the direction of the furrows. Occasionally, a miller was mistaken about the direction of the furrows, as extracts from correspondence testify: "You tell us that your top wheels must be rifled to turn counter-clockwise. We therefore understand that these millstones must be radiused to turn counter-clockwise, i.e. in the opposite direction to that in which the sun seems to revolve around the earth". Despite all the precautions taken at the time of ordering, it sometimes happened that, in the event of a dispute, we were obliged to travel to change the direction: "we sent a workman a hundred leagues from here to unravel, straighten and re-radiate two pairs of millstone; the profit is eaten twice". Special steel hardening techniques enabled certain companies, such as Kupka in Germany, to produce picks and hammers that were particularly appreciated by millstone reworkers. During the operation, the light blows emitted a cloud of siliceous dust that could cause lung ailments in specialized workers. In addition, the cutting of millstones led to professional tattoos, with steel particles from the tools embedded under the dermis. Eye diseases were also common. File:Walderveense_molen_hardstenen_molensteen.jpg|Millstone in Walderveen, Gelderland, Netherlands File:Molen_De_Engel_kunststeen.jpg|alt= File:Molensteen_kunststeen_met_pandscherpsel.jpg|alt= File:Doesburgermolen_molensteen_met_viertaksrijn.jpg|Millstone and shackle, X-shaped metal part File:Molen_het_Hert_Putten_molensteen_voor_eek.jpg|alt= File:Sint_Willebrordus_molen_molensteen_Bakel.jpg|alt= == Grinding with millstones ==

, Philippines) Grain is fed by gravity from the hopper into the feed-shoe. The shoe is agitated by a shoe handle running against an agitator (damsel) on the stone spindle, the shaft powering the runner stone. This mechanism regulates the feed of grain to the millstones by making the feed dependent on the speed of the runner stone. From the feed shoe the grain falls through the eye, the central hole, of the runner stone and is taken between the runner and the bed stone to be ground. The flour exits from between the stones from the side. The stone casing prevents the flour from falling on the floor, instead it is taken to the meal spout from where it can be bagged or processed further. The runner stone is supported by the rind, a cross- shaped metal piece, on the spindle. The spindle is carried by the tentering gear, a set of beams forming a lever system, or a screw jack, with which the runner stone can be lifted or lowered slightly and the gap between the stones adjusted. The weight of the runner stone is significant (up to ) and it is this weight combined with the cutting action from the porous stone and the patterning that causes the milling process. Millstones for some water-powered mills (such as Peirce Mill) spin at about 125 rpm. Especially in the case of wind-powered mills the turning speed can be irregular. Higher speed means more grain is fed to the stones by the feed-shoe, and grain exits the stones more quickly because of their faster turning speed. The miller has to reduce the gap between the stones so more weight of the runner presses down on the grain and the grinding action is increased to prevent the grain being ground too coarsely. It has the added benefit of increasing the load on the mill and so slowing it down. In the reverse case the miller may have to raise the runner stone if the grain is milled too thoroughly making it unsuitable for baking. In any case the stones should never touch during milling as this would cause them to wear down rapidly. The process of lowering and raising the runner stone is called tentering and lightering. In many windmills it is automated by adding a centrifugal governor to the tentering gear. Depending on the type of grain to be milled and the power available the miller may adjust the feed of grain to stones beforehand by changing the amount of agitation of the feed-shoe or adjusting the size of the hopper outlet. Milling by millstones is a one-step process in contrast with roller mills in modern mass production where milling takes place in many steps. It produces wholemeal flour which can be turned into white flour by sifting to remove the bran. File:MillingEquipment-01-tag.jpg|Millstone feeder File:Auget.gif|Principle of the grain feeding system File:Meule_à_grain_moulins_de_Kerouat_Finistère_France.JPG|View from the eyelet File:La_trempure.jpg|The dipping mechanism adjusts the distance between the two millstones (Gentinnes watermill - Belgium). ==Symbolism==

Symbolism in the Bible Millstones were often essential objects within a community. For that reason, they gain multiple symbolic meanings and symbolism within mythology, folklore, and the Bible. The Hebrew Bible admonishes (Deuteronomy 24:6): "No one shall take a lower millstone, nor an upper millstone, in pledge [for the payment of a debt], for that would be tantamount to taking away a life in pledge." The rabbis have explained that not only a millstone cannot be taken as security for a pledge, but anything in which the life of man depends cannot be taken as security for a pledge. The Bible heavily utilized millstone symbolism within its various proverbs. A common one is the millstone's proverbial designation of something as a great weight, as seen in Matthew 18:6 Likewise, due to the exhausting physical labor associated with the earliest millstones, they were symbolic of hard work and accredited as a menial task given to the lowest form of a laborer. This is not the only symbolic meaning of millstones within the Bible; millstones were also used as a symbol of civilization, prosperity, and comfortable living. Other symbolism Out of the Bible, the millstone can be seen as a symbol of transformation, death, and rebirth. This is due to the strenuous amount of work and effort that goes into utilizing a millstone to grind grain into flour. Other symbolic meanings associated with millstones include fertility and abundance. In Korea, a practice existed in which the husband would use a millstone while his wife was in childbirth, hoping that he could share her pain. The fer-de-moline ("mill-iron") or millrind, which attaches to the millstone and transfers to it the torque of the drive-shaft, is also a common heraldic charge, used as canting arms by families named Mills, Milles, Turner, etc. File:Höör vapen.svg|A millstone in the arms of Höör, Sweden File:Askola.vaakuna.svg|A millstone in the arms of Askola, Finland == Photo gallery ==

File:Woldegk-Roemermuehle.JPG|alt= File:Handkorenmolen_in_IJzendijkse_Molen.jpg|Millstone at Augusta Raurica File:Augustaraurica_millstone.jpg|alt= File:Mons_moulins_Huile.jpg|Ancient communal mills (Lambert mills) for oil, fulling, wheat, on the Siagnole, Mons (Var) File:EC_Mill_with_Petroleum_Engine.JPG|Millstone powered by internal combustion engine File:Levens_moulin-farine.jpg|Former flour mill (Levens, France). File:Meule_a_grain_chine.jpg|Grain millstone in the snow in northern China. File:Meule_de_moulin_(Lotbinière).JPG|A millstone used to support a sundial at Domaine Joly in Lotbinière, Quebec. File:Meule_aux_Jardins_de_Métis_1.JPG|Garden Millstone at Jardins de Métis, Quebec. File:Encyclopédie_-_illustration_of_a_powder-mill_(18th_Century).jpg|Encyclopedia. Manufacture of gunpowder File:Meule_gypse.JPG|Pair of millstones used to grind gypsum before firing. Berzé-la-Ville File:QP western stone across jeh.jpg|One of the Dutch Kills Millstones displayed in a NYC park. == See also ==

Bibliography • (fr) Meules à grains. Actes du colloque international de La Ferté-sous-Jouarre, 16-19 mai 2002 archive, Éditions Ibis Press - Éditions de la maison des sciences de l'homme () • (fr) Alain Belmont, La Pierre à pain. Les carrières de meules de moulins en France, du Moyen ge à la révolution industrielle, Presses universitaires de Grenoble, 2006, 2 vol. () • (fr) Bertrand Gille (s. dir.), Histoire des techniques, Gallimard, coll. "La Pléiade", 1978. () • (fr) Bertrand Gille, ''Les sources statistiques de l'histoire de France - Des enquêtes du xviie siècle à 1870'', Centre de recherches d'histoire et de philologie de la IVe section de l'École pratique des hautes études, 1964. • (fr) Auguste Armengaud, Claude Rivals, ''Moulins à vent et meuniers des pays d'oc'', Toulouse, Loubatières, 1992 () • (fr) Marie-Claire Amouretti, ''Le pain et l'huile dans la Grèce antique. De l'araire au moulin'', Besançon, Les Belles Lettres, ALUB, (328), 1986 () • (fr) Jean-Pierre Brun. ''Archéologie du vin et de l'huile. De la préhistoire à l'époque hellénistique''. Éditions errance, 2004 () • (fr) Jean-Pierre Brun. ''Archéologie du vin et de l'huile dans l'Empire romain''. Éditions errance, 2004 () • External links • Millstone Dressing Tools • European millstone quarries: a database • Abandoned Millstones - Peak District • Video clip demonstrating millstone dressing • Millstones & Querns on Flickr • Atlas of the millstones of France and Europe archive • Millstones. Recherche, protection et valorisation d'un patrimoine industriel européen (Antiquité-xxie s.) archive. International symposium, Grenoble - Thursday 22nd to Sunday 25 September 2005 - Maison des Sciences de l'Homme-Alpes. • Techniques in Greco-Roman antiquity archive. • The Dussart mill archive • History of anille archive • Le moulin de la Mousquère archive Detail of the grindstone's grain-feeding mechanism • Millstone" encyclopedia article on wikisources • [PDF] Processing techniques archive • [PDF] And man created the millstone archive • Fédération Des Moulins de France archive, Monde des Moulins magazine archive • Fédération Française des Associations de sauvegarde des Moulins archive, Moulins de France magazine archive • Rotary hand mills archive == References ==