Today, we're going to tilt at windmills. The
University of Houston's College of Engineering
presents this series about the machines that make
our civilization run, and the people whose
ingenuity created them.
Don Quixote dwelt in the
twilight of the age of chivalry -- in the
fourteenth or fifteenth century -- but he was a
creature of the late-16th-century author Cervantes.
Early in the story, he cries,
Look there, my friend Sancho Panza, where thirty
or
more monstrous giants present themselves, all of
whom
I mean to engage in battle and slay!
And he points to a very large presence
of power-generating windmills dotting the Spanish
landscape.
The windmill rapidly came into wide use in Europe
during the twelfth century -- 200 years before
Quixote and 400 years before Cervantes. A debate
has gone on as to whether it was brought to Europe
from the Holy Land, or vice versa, by crusaders.
The current best guess is that it originated in
Northern Europe. The waterwheel had been in wide
use for a hundred years when the windmill came
along. Windmills were more complicated, and they
were at the mercy of the sometimes fickle winds.
But they could deliver more power than a
waterwheel, and they made it possible to grind
grain where there were no streams -- in places like
the Dutch lowlands and the Spanish plains.
By 1760 windmills had reached an astonishing level
of sophistication. They were equipped with
automatic regulators that controlled the speed of
rotation, that adjusted the pitch of the fan blades
for maximum power at a given wind speed, and that
oriented the fan so it always faced directly into
the wind. When they were were used for milling,
they were equipped with devices that regulated the
pressure of the millstones on the grain.
But it was also in the 1760s that Watt developed a
vastly improved steam engine. As the 18th century
ended, windmill development was abandoned in favor
of these new engines. Watt was the Quixote who
really slew the windmill.
Of course, windmills didn't go away completely.
Today they're still a choice power supply for
isolated use where there's no commercial
electricity -- for filling cattle watering troughs
out on the prairie, for example. They played a
large role in opening up the American West.
Lately we've seen a new interest in wind power.
Latter-day engineers are concocting a dizzying set
of improvements in the hope of using windmills for
electric power generation.
But 18th-century windmills remain an almost
forgotten glory that might well impress any
engineer today. For example, the variable-pitch
propellors used in these mills over 200 years ago
are an innovation that airplane designers didn't
rediscover until the 1930s.
I'm John Lienhard, at the University of Houston,
where we're interested in the way inventive minds
work.
(Theme music)
George, B., Reaping the Wind. American Heritage
of Invention and Technology, Vol. 8, No. 3,
Winter 1993, pp. 8-14.
Kealey, E., Harvesting the Air: Windmill
Pioneers in Twelfth-Century England.
Berkeley: University of California Press, 1987,
Chapter 7.
Mayr, O., The Origins of Feedback
Control. Cambridge, MA: MIT Press, 1970.
Righter, R.W., A Few Words About This Picture.
American Heritage of Invention and
Technology, Vol. 7, No. 1, Spring/Summer
1991, pp. 28-31.
White, L. Jr., Medieval Technology and Social
Change. New York: Oxford University Press,
1966, Chapter 3.
This episode has been greatly revised as Episode 1359. For more on
windmills, and for additional reference material,
see Episodes 537, 552, 607,
and 766.
From the October, 1896,
Scribner's Magazine
Artist's sketch of an actual windmill on the
Quixote's plains of La Mancha
The Engines of Our Ingenuity is
Copyright © 1988-2018 by John H.
Lienhard.
Previous
Episode | Search Episodes |
Index |
Home |
Next
Episode
