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Piddington's Law of Storms
Fri Dec 31, 2004
Listen in RealAudio 
We remember Henry Piddington, a 19th century British official in colonial India, mostly
as the man who coined the word "cyclone" to describe rotating storms. The former sea
captain introduced the word in his 1884 landmark book, "The Sailor's Horn-Book for
the Law of Storms." Hi, I’m Bryan Yeaton for The Weather Notebook.
The first edition warned sailors that severe tropical storms, akin to Atlantic hurricanes,
in the Indian and China Seas exhibited consistently changing winds that shifted
counter-clockwise as the storm passed.
Piddington described how the barometer behaved as the storm approached, giving a
ballpark distance to the storm’s center, which he called "the fatal centre." He also
recognized that the storm’s right side was the more dangerous.
Piddington wanted to teach mariners how to avoid the storm’s full-on winds, how best
to sail within them when unavoidable, and how to profit from the tempest by using the
its fringe winds to speed the ship onward. To do so, the captain must ignore compass
direction and think in terms of the quadrants of a circular storm.
The book included two transparent horn cards, one for counter-clockwise winds for the
Northern Hemisphere, one for clockwise winds for the Southern Hemisphere, that had
wind arrows drawn on them indicating which wind direction would be blowing around
the storm. The captain placed the card on his chart, matching the chart’s wind arrow
with the currently observed wind direction. The card now indicated the wind directions
relative to the storm’s center. With these cards, mariners had the hurricane in their
hand.
"The Sailor’s Horn Book" became an immediate and lasting success; for many years,
the only recognized textbook on marine storms.
Thanks to our contributing writer, meteorologist Keith Heidorn. The Weather Notebook
is a program of the Mount Washington Observatory, funded by Subaru of America. Find
all of our shows online at www.weathernotebook.org.
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