I don’t think I’d actually heard a glass harmonica played until today whilst downloading some Mozart. Or I have heard it in the background and never investigated what the sound was. I wonder how widespread it’s use was in Mozarts time? or is now? What an unusual sound.
Here’s Mozart’s Adagio & Rondo in C minor, K.617: Adagio played with glass harmonica. (*it’s also recorded with piano instead of the harmonica)
Mozart’s Adagio & Rondo in C minor, K.617 I. Adagio
Here’s one being played on YouTube