Mr Parkes is describing an orchestral "nightingale".

A small resevoir which you fill with water/beer/G+T and a fipple like on a recorder. you blow into the chamber, which makes waves in the liquid, changing the shape of the airspace, so changing the pitch.

The romans used to have a thing called a "Hydraulis" which was a bloody great big water driven pipe organ, if that's any help.

EJ