A mill race is the current of water that turns a water wheel, or the channel (sluice) conducting water to or from a water wheel. The race leading to the water wheel is called the head race, and the race leading away from the wheel is called the tail race.
A mill race has many geographically specific names, such as leat, lade, flume, goit, penstock. These words all have more precise definitions and meanings will differ elsewhere. The original undershot waterwheel, described by Vitruvius was a run of the river wheel placed so a fast flowing stream would press against and turn the bottom of a bucketed wheel.In the first meaning of the term, the millrace was the stream; in the sense of the word- there was no channel, so no race.
As technology advanced, the stream was dammed forming a weir. This increased the head of water. Behind the weir was the millpond, or lodge. The water (millrace) was channelled to the waterwheel by a sluice or millrace- this was the head race. From the waterwheel, the water was channelled back to the stream by a sluice known as the tail race. When the tail race from one mill led to another mill where it acted as the head race this was known as the mid race. The level of water in the millrace could be controlled by a series of sluice gates.
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A head race
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Storckensohn water head race, or flume.
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Tail race rejoining River Meon.
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Cogglesford Mill: a covered head race and the by-pass weir
Famous quotes containing the words mill and/or race:
“Mathematics may be compared to a mill of exquisite workmanship, which grinds your stuff of any degree of fineness; but nevertheless, what you get out depends upon what you put in; and as the grandest mill in the world will not extract wheat- flour from peascods, so pages of formulae will not get a definite result out of loose data.”
—Thomas Henry Huxley (1825–95)
“These battles sound incredible to us. I think that posterity will doubt if such things ever were,—if our bold ancestors who settled this land were not struggling rather with the forest shadows, and not with a copper-colored race of men. They were vapors, fever and ague of the unsettled woods. Now, only a few arrowheads are turned up by the plow. In the Pelasgic, the Etruscan, or the British story, there is nothing so shadowy and unreal.”
—Henry David Thoreau (1817–1862)