Public Humidity Hi-Hats

A giant weather house erected in the center of the town responds to changes in humidity by modifying the tension on an oversized hi-hat. A hi-hat under more tension is more responsive, so the audible effect of a reduction in humidity is a hi-hat that plays at a faster tempo (when operated by an automatic pedal-kicker).

Along with the Public Temperature Bells and the Visibility Snare, this is just another member of an array of percussive devices that accompany Big Ben's hourly chime according to the current meteorological parameters.