Environmental Engineering Reference
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early as historical records of human civilisation exist. The exact
origin of the windmill, a wind-powered system used to grind
agricultural products such as grain, is a subject of debate. The
oldest windmills are thought to have been developed concurrently
with the large agricultural systems of the ancient civilisations in
the Near East.
Figure 5.1
Model of a “Persian Windmill” in the Deutsches Museum,
Munich.
Evidence from records of the era as well as more modern
instances of these windmills indicate that they were vertical-
axis in orientation with sails spinning around a central shaft
in order to turn a stone at the base that was used for grinding.
Windmills with a horizontal-axis in orientation first appeared in
historical records in 12th century England and nearby regions.
No direct link between vertical-axis windmills of the Near East
and horizontal-axis windmills of Western Europe has been proven
though various theories have been proposed.
The most popular account is that soldiers earlier in the century
observed windmills during the Crusades. Other accounts suggest
the technology was developed independently as an extension
of watermill technology that already existed in the regions. By
whatever source of invention, the windmills of Western Europe
took on their own distinct character in the form of the “post-mill”,
the horizontal-axis windmill attached to a post that encases the
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