Meteorology with Leeches - Meet The Tempest Prognosticator

Culper Bell

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Joined
May 2, 2019
Location
Greensboro, North Carolina
You've probably heard of blood letting practices with leeches and perhaps even modern medicinal usage for leeches. But did you know that leeches were a relatively effective way to predict storms?

British inventor George Merriweather utilised the leech's natural ability to feel the changes in atmospheric pressure to invent a contraption to assist farmers and clergymen that had to travel great distances. Standing more than three feet tall, the ornate contraption housed twelve leeches within bottles accompanied by a small amount of rain water arranged in a circular fashion. Naturally during rainfall leeches travel up to the surface from water sources in search of meals, though in the bottles they performed the same action: They rose out of the rain water to the bottleneck which in turn would dislodge a whalebone pin that allowed for a large bell to ring [Though the ringing of this bell required the efforts of multiple leeches].


Tempest Prognosticator.jpg


Tempest.png


It was a relatively accurate system though it lacked the ability to tell the direction of a storm and more precise timing than knowing a storm was coming some time that day. It did however get featured in the Crystal Palace in London's Hyde Park as part of a long series called the "Great Exhibition of the Works of Industry of All Nations" hosted by both Queen Victoria and Prince Albert in 1851.

Merryweather had high hopes for his invention and assumed it would be found on ships and farms, though it never caught on. The leeches were seen to be high maintenance and the Tempest Prognosticator fell to obscurity as more accurate forms of meteorology developed.

Further reading:

https://www.atlasobscura.com/articles/leeches-predict-weather-tempest-prognosticator
https://whitbymuseum.org.uk/whats-here/collections/special-collections/tempest-prognosticator/
 
Fascinating! Thanks so much for this post! I just visited last week the Country Doctor Museum in Bailey, NC and saw some fancy "Leech Jars" - the storage vessels for medical leeches.

Believe it or not, some are really fancy and attractively decorated. The ironstone ones have perforated lids to allow the little critters to breathe I suppose. :D
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From the Smithsonian https://americanhistory.si.edu/collections/search/object/nmah_736008
 
I was happy to make this post seeing as no one else had before, in addition to the Tempest Prognosticator being one of those odd things you just can't forget :giggle: I'm glad it's been well appreciated this far!

I've been meaning to get out to Bailey myself to see the place though it's good to hear you enjoyed yourself. It is amusing though that leeches used to be stored in those ornate jars seeing as most people are typically skeeved out by them nowadays. I'm sure most would prefer they stay in simple pewter cases rather than a deceptively elegant jar :biggrin:
 
Thank you! It really is tragic, part of me wishes the Tempest Prognosticator caught on and that there was a brief period of time where people casually carried around leeches.

That would have made for shocking but humorous reading, considering other strange customs during the 19th century :giggle:
 
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