Ernst Chladni at the understanding of electron orbitals. Since at least 1738, a musical instrument called a "Glasspiel" or "verrillon", created by filling beer glasses with varying amounts of water, was popular in Europe. The beer glasses were struck by wooden mallets shaped like spoons to produce "church and other solemn music". Benjamin Franklin was sufficiently impressed by a verrillon performance on a visit to London in 1757 that he created his own instrument, the glass armonica, in 1762. Franklin's armonica inspired several other instruments, including two created by Chladni. In 1791, Chladni invented the musical instrument called the "euphon" (not to
Harmonica performing on another instrument with their hands (e.g., an acoustic guitar) often use an accessory called a "neck rack" or "harmonica holder" to position the instrument in front of their mouth. A harmonica holder clamps the harmonica between two metal brackets, which are attached to a curved loop of metal that rests on the shoulders. The original harmonica racks were made from wire or coat hangers. Models of harmonica racks vary widely by quality and ease of use, and it quite often takes experimenting with more than one model of harmonica rack to find one that feels suitable for each