Hummadruz

Sir, Richard Foskett (letter, May 26) asks if the spring hum has vanished. The sound he refers to has been known as the hummadruz, and was even noted by William Cobbett. I encountered it near Halifax in 1977, and 15 years ago started some research into this curiously unsettling experience, which remains unexplained. In the course of research I have received and read of a considerable number of environmental “hums” — more than half seem most likely to be attributable to some technological cause and therefore a modern phenomenon.

Yet still a reasonable number are of a more “traditional” nature — a buzzing like a swarm of insects, only without an apparent physical source, and generally heard on hot, still days. So the bucolic hummadruz is still to be heard, and its origin, perhaps frustratingly, is still to be explained.