The glass armonica, also known as glass harmonica, was invented by Benjamin Franklin in 1761. It consists of glass bowls tuned by size, mounted one inside each other with cork on a metal spindle. The glasses are made to spin with a flywheel attached to a foot treadle. Moistened fingers rub the exposed rims of the glasses to produce one of the most beautiful sounds ever created by man. Jefferson, Mozart, Beethoven, and Mesmer are only a few of the famous men associated with the armonica. The glass armonica is believed to have caused health problems in the 18th century due to the lead content in the glass and the lead paint used on the rims of the glasses to identify the notes. Performers complained of loss of feeling in their hands and some players even suffered nervous breakdowns at the end of their careers. People became very frightened of the armonica, and by 1830, it was all but extinct. The glass armonica was revived in 1984 by master glass blower Gerhard Finkenbeiner of Boston, MA. Instead of using regular glass, he blows pure quartz into bowls that are now used. Dean Shostak added the flywheel to the instrument, and the rest is history.