In 1762, Benjamin Franklin, then in London, wrote a letter to a colleague in Italy describing his latest invention, a musical instrument he called the "armonica," which was based on how rubbing a wet finger on the rims of wine glasses could produce musical tones. In contrast to earlier sets of wine glasses that could be tapped or rubbed, Franklin put a set of glass bowls differing in size on a horizontal rod turned by a food treadle, thus freeing both hands for touching the rotating glasses and allowing musicians to play more than two glasses at a time, as well as eliminating the nuisance of water tuning. Franklin played his instrument for pleasure, to manipulate the "passions" (emotions) and to treat melancholia. Nevertheless, late in his lifetime some individuals began to view glass armonica music differently, alleging it could cause nerve damage and mental problems. Here, we look at how Franklin used his glass armonica to manipulate the passions and examine what he must have thought about it supposedly causing health problems. We present Franklin as an empiricist, whose focus was more on results than theories; as an astute student of human behavior understanding the power of charms and other "nonsense"; and as a man of medicine living in an era when much was being attributed to the nerves, even though next to nothing was really known about the underlying nerve force.
