Four-Inch Checkerboard

 

It’s a musical instrument with a lot of names: armonica, glass harmonium, harmonica de franklin, and bowl organ are just a few. It was one of Benjamin Franklin’s many inventions, conceived after the founding father saw a musician play at Cambridge on a set of water-filled glass wine goblets. Franklin designed a series of graduated glass bowls that rotate on a horizontal spindle. A performer with moist fingers could play it much like a keyboard, with lower notes to his left and higher to his right. Franklin was thrilled by the ethereal sound it made, and by the fact the player had broad control of dynamics (a rarity for musical instruments in the 1700’s). Many people found its music disorienting, and some believed it caused madness, primarily because of the way we perceive sound. Above 4khz we use volume for location. Below 1khz we use phase differences. The armonica plays in a range that confuses the brain.