Glass harmonica Franz Mesmer also played the armonica and used it as an integral part of his Mesmerism. An original Franklin armonica is in the archives at the Franklin Institute in Philadelphia, having been donated in 1956 by Franklin's descendants after "the children took great delight in breaking the bowls with spoons" during family gatherings. It is only placed on display for special occasions, such as Franklin's birthday. The Franklin Institute is also the home of the Benjamin Franklin National Memorial. A website has attempted to catalog publicly known Franklin-era glass armonicas. The Museum of Fine Arts, Boston has an early 19th-century
Glass harmonica and locate ranges of sounds. Above 4 kHz people primarily use the "loudness" of the sound to differentiate between left and right ears and thus triangulate, or locate the source. Below 1 kHz, they use the "phase differences" of sound waves arriving at their left and right ears to identify location. The predominant pitch of the armonica is in the range of 1–4 kHz, which coincides with the sound range where the brain is "not quite sure", and thus listeners have difficulty locating it in space (where it comes from), and discerning the source of the sound (the materials and