Benjamin Franklin invented the glass harmonica, patterned after people who wet their fingers and ran them around the rims of glasses, playing tunes. A foot pedal rotates them. Mozart heard it in London when he was 8. His father wanted one for the family, but it never happened. 30 years later, Mozart heard a blind virtuoso in Vienna, and composed several pieces for glass harmonica. We heard one. Eerie, a little like organ music or merry-go-round music. Not something I would want to hear too often, given the many other wonderful Mozart compositions.