Millstone

The runner stone is supported by a cross-shaped metal piece (millrind or rynd) fixed to a "mace head" topping the main shaft or spindle leading to the driving mechanism of the mill (wind, water (including tide), or other means).

[4]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.

The Australian grindstones usually comprise a large flat sandstone rock (for its abrasive qualities), used with a top stone, known as a "muller", "pounder",[5] 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.

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).

[7] 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.

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.

In his typology of percussion, André Leroi-Gourhan defines several families of gestures, three of which are essential for the preparation of raw materials: Until the invention of the watermill, mills operated using "strength-powered", i.e. the force of animals or people.

While the manufacture of apod millstones from blocks of stone naturally polished in a riverbed was once within the reach of many farmers, the production of tripode metates requires specialized craftsmanship.

Fruits are ground into juices, beans or boiled vegetables, ingredients are added to various spicy sauces and, above all, corn is used to make the tortillas that form the basis of every meal.

Maize or nixtamal can be ground for preparations other than patties: tamales, pozole, atole, pinole, and masa, with variations in the fineness of the grind depending on the use.

Some authors do not agree on its geographical origin, located for some "towards Carthage and the Syrian-Egyptian region", "simultaneously in Spain[23][24] and England" for others, and even though it was found in China in the 1st century BC.

The more sharply tapered inner surfaces of the millstones ensured that the grains flowed more quickly under the effect of gravity, but the quality of the flour obtained remained mediocre.

The speed of rotation became higher, providing a greater gyroscopic effect, but also requiring the installation of a system of claws fixed with molten lead on the upper side of the movable wheel, to hold it in place around the pivot.

During the Late Antiquity, the donkey mill retreated, probably disappearing after the 5th century as a result of the expansion of the watermill, then the windmill, except in Sardinia, where it remained until the 20th century.The Hellenistic period also saw the appearance of the olive crusher, which the Romans called the trapetum.

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.

Columella asserts that,[31] 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.

An inscription from the Phrygian town of Orcistus,[34] 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".

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.

[36] 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.

[40] 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.

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.

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.

[45] 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.

Corfélix stones have exceptional compressive strength on the order of solid basalt (190 MPa), 98% silica, fairly coarse grain, and medium to high porosity.

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".

Between the furrows, the millstone is covered with fine grooves called feathering or cracking, also cut into the stone, to make it more aggressive and thus better able to grind the grains.