Early history , a funerary figurine placed in the tomb to work in place of the deceased.
Brooklyn Museum. flour mill, 2005 in
Southern Ontario, 2009 The Greek geographer
Strabo reported in his
Geography that a water-powered grain-mill existed near the palace of king
Mithradates VI Eupator at
Cabira,
Asia Minor, before 71 BC. The early mills had horizontal paddle wheels, an arrangement which later became known as the "
Norse wheel", as many were found in Scandinavia. The paddle wheel was attached to a shaft which was, in turn, attached to the centre of the
millstone called the "runner stone". The turning force produced by the water on the paddles was transferred directly to the runner stone, causing it to grind against a stationary "
bed", a stone of a similar size and shape. The rotating mill is considered "one of the greatest discoveries of the human race". It was a very physically demanding job for workers, where the slave workers were considered little different from animals, the miseries of which were depicted in iconography and
Apuleius'
The Golden Ass. The peak of Roman technology is probably the
Barbegal aqueduct and mill where water with a 19-metre fall drove sixteen
water wheels, giving a grinding capacity estimated at 28 tons per day. Water mills seem to have remained in use during the post-Roman period. Manually operated mills utilizing a crank-and-connecting rod were used in the
Western Han dynasty. There was an expansion of grist-milling in the
Byzantine Empire and
Sassanid Persia from the 3rd century AD onwards, and then the widespread expansion of large-scale
factory milling installations across the
Islamic world from the 8th century onwards. Geared gristmills were built in the medieval
Near East and
North Africa, which were used for grinding grain and other seeds to produce
meals. Gristmills in the Islamic world were powered by both water and wind. The first
wind-powered gristmills were built in the 9th and 10th centuries in what are now Afghanistan, Pakistan and Iran. The Egyptian town of
Bilbays had a grain-processing factory that produced an estimated 300 tons of flour and grain per day. From the late 10th century onwards, there was an expansion of grist-milling in Northern Europe. Limited extant examples of gristmills can be found in Europe from the
High Middle Ages. An extant well-preserved waterwheel and gristmill on the
Ebro River in Spain is associated with the
Real Monasterio de Nuestra Senora de Rueda, built by the
Cistercian monks in 1202. The Cistercians were known for their use of this technology in Western Europe in the period 1100 to 1350.
Classical British and American mills Grist Mill in
Massachusetts, 2014 , a 17th-century operational mill in
Cheshire, England, 2008 Although the terms "gristmill" or "corn mill" can refer to any mill that grinds grain, the terms were used historically for a local mill where farmers brought their own grain and received ground meal or flour, minus a percentage called the "miller's toll". Early mills in England were almost always built by the local
lord of the manor and had the exclusive right (the right of
mulcture) to a proportion on all grain processed in the community. Later, mills were supported by farming communities and the miller received the "miller's toll" in lieu of wages. Most towns and villages had their own mill so that local farmers could easily transport their grain there to be milled. These communities were dependent on their local mill as bread was a staple part of the diet. Classical mill designs are usually
water-powered, though some are powered by the wind or by livestock. In a watermill a
sluice gate is opened to allow water to flow over or under a
water wheel to make it turn. In most watermills, the water wheel was mounted vertically, i.e., edge-on, in the water, but in some cases it was aligned horizontally (the tub wheel and so-called
Norse wheel). Later designs incorporated horizontal steel or cast iron
turbines, which were sometimes refitted into the old wheel mills. In most wheel-driven mills, a large gear-wheel called the
pit wheel is mounted on the same axle as the water wheel and this drives a smaller gear-wheel, the
wallower, on a main
driveshaft running vertically from the bottom to the top of the building. This system of gearing ensures that the main shaft turns faster than the water wheel, which typically rotates at around 10
rpm. The millstones themselves turn at around 120
rpm. They are laid one on top of the other. The bottom stone, called the
bed, is fixed to the floor, while the top stone, the
runner, is mounted on a separate spindle, driven by the main shaft. A wheel called the
stone nut connects the runner's spindle to the main shaft, and this can be moved out of the way to disconnect the stone and stop it turning, leaving the main shaft turning to drive other machinery. This might include driving a mechanical
sieve to refine the flour, or turning a wooden drum to wind up a chain used to hoist sacks of grain to the top of the mill house. The distance between the stones can be varied to produce the grade of flour required; moving the stones closer together produces finer flour. This process, which may be automatic or controlled by the miller, is called
tentering. The grain is lifted in sacks to the "sack floor" at the top of the mill by a
hoist. The sacks are then emptied into bins, from which the grain falls through a hopper to the millstones on the "stone floor" below. The flow of grain is regulated by shaking it in a gently sloping trough (the "slipper") from which it falls into a hole in the center of the runner stone. The milled grain (flour) is collected as it emerges through the grooves in the runner stone from the outer rim of the stones and is fed down a chute to be collected in
sacks on the ground or "meal floor". A similar process is used for grains such as
wheat, to make flour, and for
maize, to make
corn meal. In order to prevent vibrations from the millstones shaking the building apart, the stones were usually placed on a separate timber foundation, known as a husk, which was not attached to the mill walls. That isolated the building from vibrations coming from the stones and the main gearing, and also allowed for easy re-leveling of the foundation to keep the millstones perfectly horizontal. The lower bedstone was placed in an inset in the husk, with the upper runner stone above the level of the husk.
The automatic mill American inventor
Oliver Evans revolutionized the labor-intensive process of early mills at the end of the eighteenth century when he automated the process of making flour. His inventions included the Elevator, wood or tin buckets on a vertical endless leather belt, used to move grain and flour vertically upward; the Conveyor, a wooden auger to move material horizontally; the Hopper Boy, a device for stirring and cooling the newly ground flour; the Drill, a horizontal elevator with flaps instead of buckets (similar to the use of a conveyor but easier to build); and the Descender, an endless strap (leather or flannel) in a trough that is angled downward, the strap helps to move the ground flour in the trough. Most importantly, he integrated these into a single continuous process, the overall design later becoming known as the Automatic (or Automated) mill. In 1790 he received the third Federal patent for his process. In 1795 he published "The Young Mill-Wright and Miller’s Guide" which fully described the process. Evans himself did not use the term gristmill to describe his automatic flour mill, which was purpose designed as a merchant mill (he used the more general term "water-mill"). In his book his only reference to "grist" (or "grists") is to the small batches of grain a farmer would bring in to have ground for himself (what would be generally called barter or custom milling). In his book, Evans describes a system that allows the sequential milling of these grists, noting that "a mill, thus constructed, might grind grists in the day time, and do merchant-work at night." Over time, any small, older style flour mill became generally known as a gristmill (as a distinction from large factory flour mills). ==Modern mills==