Invented by Benjamin Franklin, the glass armonica consists of a series of glass bowls of varying sizes arranged on a rotating spindle. The player touches the rims of the rotating bowls with moistened fingers to produce haunting, ethereal tones. It became wildly popular in Europe, with Mozart and Beethoven writing music for it. However, a strange legend arose that the instrument could cause madness, melancholia, and even physical illness in both performers and listeners. Some modern historians suggest this 'glass armonica madness' might have been lead poisoning, as the glass used at the time had high lead content that was absorbed through the fingertips. Others believe the high-frequency vibrations simply unnerved people. Though it fell into obscurity for over a century, the instrument is still used today in film scores to create 'magical' or 'unsettling' atmospheres.