From David Bent, Green's Mill & Science Centre
Yet another phenomenon known to our forebears has been “discovered” in modern times (5 August, p 34). In the 19th century, windmillers were sufficiently familiar with wind-generated tones from their mills to give the effect a name: they called it “blowing the horn”. This usually happened in a strong wind at the end of the day’s work, when the shutters along each sail were opened, allowing the wind to blow through the gaps.
When the eight-sailed mill at Heckington in Lincolnshire was restored to full working order in the early 1990s, a tone of about 240 hertz was generated when the mill was at rest in a wind of force 4 or above. This was cured by wrapping a wide-spaced helix of twine around each shutter to disrupt the airflow and allow the village a good night’s sleep.
From Anne Silk
Visiting Malta recently, I walked out of the Hilton hotel towards Portomaso crossing over the small inlet off St Julians Bay. Low metal railings lined the road over the bay. A glorious day, but who or what was singing the strange melody I could hear so loudly? With a professional interest in acoustics and as a choral singer myself, I realised that the wind, funnelling into the inlet, itself surrounded by tall buildings, was producing the strange musical sounds, in the human voice range around 500 hertz. Haunting melodies indeed!
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Princes Risborough, Buckinghamshire, UK
Sneinton, Nottinghamshire, UK
