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n … and if you think that’s weird, then what do younmake of the Tempest Prognosticator? This fabulous contraption was invented bynthe aptly named Dr George Merryweather, who was inspired by a couple of linesnfrom the poem Signs of Rain by Edward Jenner,
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n“The leech, disturb’d, is newly risen.n
nQuite to the summit of his prison.”n
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| Edward Jenner – Signs of Rain |
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nThis couplet brought to the good Doctor’s mind anletter written by another poet, William Cowper, to his cousin Lady Hesketh, dated October 10thn1787, in which he describes the behaviour of a leech he owns,
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n“Yesterday it thundered, last night it lightened,nand at three this morning I saw the sky as red as a city in flames could havenmade it. I have a leech in a bottle that foretells all these prodigies andnconvulsions of nature. No, not as you will naturally conjecture, by articulatenutterance of oracular notices, but by a variety of gesticulations, which here Inhave not room to give an account of. Suffice it to say, that no change ofnweather surprises him, and that, in point of the earliest and most accuratenintelligence, he is worth all the barometers in the world.”n
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| William Cowper – Letter to Lady Hesketh – 1787 |
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nMerryweather began to observe leeches, and notednthat some, but not all, would indeed crawl upwards in the bottle in which theynwere kept prior to a thunderstorm. He selected those that were, in his opinion,nthe most prescient and put a dozen of them (his ‘jury of philosophicalncounsellors’) into pint bottles, which he arranged in a circle so that thenleeches could see each other and not suffer the ‘affliction of solitary confinement’.
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| The Medicinal Leech |
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nIn the neck of each bottle he placed a metal tube, into which the leech couldncrawl, and attached to each tube was a small whalebone trigger, which wasndislodged by the movement of the leech. This, by means of a mouse-trap likencontrivance, caused a spring-loaded hammer to strike a bell placed at thencentre of the circle of bottles. The ringing of the bell indicated the adventnof a thunderstorm, and the more times the bell rang, the greater the likelihoodnof a storm. Merryweather deduced that the leeches were acting due to a changenin atmospheric electricity prior to inclement weather, and he toyed with thennotion of calling his device The Atmospheric Electro-Magnetic TelegraphnConducted by Animal Instinct but thought better of it and called it insteadnhis Tempest Prognosticator –
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n“… two words expressive enough for all foreignersnto understand.”n
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| The Tempest Prognosticator |
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nDr Merryweather was a surgeon in Whitby, Yorkshirenand a member of the Whitby Literary and Philosophical Society, to whomnhe unveiled his invention in a three-hour presentation on February 27thn1851.
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| G Merryweather – An Essay Explanatory of the Tempest Prognosticator |
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nThe tone of the paper is excellently maintained throughout –it is eruditenand suitably scholarly, meticulously referenced and learnedly footnoted, andnrambles off in unexpected directions only to be brought expertly back to itsnsubject, and it is all done with a tongue held very firmly in cheek.nMerryweather was having a very good time with his Tempest Prognosticator, andnhaving picked up his ball he certainly ran with it.
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| Merryweather’s Letter |
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nHe wrote a letter to thencommittee that was organising the Great Exhibition of 1851, asking if he mightnhave space to present this great benefit to humanity (with a wonderful provisonthat his device be protected from potential piracy whilst on display) and,nperhaps to his surprise, he was given permission to take it to London. ThenGreat Exhibition opened on May 1st 1851 and Dr Merryweather’snTempest Prognosticator was shown to the world. Constructed from French-polishednmahogany, polished brass, silver, ivory and glass, and fashioned like an Indianntemple, it was a great success.
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| Detail of a replica Tempest Prognosticator |
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nMerryweather applied to the Admirality to havenhis machines installed at sea ports but for some strange reason his applicationnwas declined, the Navy Board plumping instead for Robert Fitzroy’s Storm GlassnBarometer. The original mechanism hasnbeen lost, but replicas have since been made (notably for the 1951 Festival ofnBritain).
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| Build Your Own Tempest Prognosticator |
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