This whole business remainds me of 2 "things": a) an instrument, call (if I remember well) glass harmonica. It is made of a set of glass bowls of different sizes all tuning on a horizontal axis located at their center and dipping in water. The player touches the bowl(s) to play either melody or arpeggios. It was made in the XIXth century and discontinued as having the reputation of making people crazy...Other weird instruments were invented (and discontinued) in that period. Musical encyclopedists may correct/reference this... b) a report that I saw eons ago on CBC about this diver "communicating with killer whales in British comlumbia. He was using a metal violin, a metallic drum with metal spikes of different length attached to the rim, that is bowed. He was playing that thing at the sea surface with the flat part of the drum on the water. The whales seemed to like it...

Salut,

JL