Anne Ford it was considered controversial for a woman to play the "masculine" viola da gamba, referred to at the time as the "viol di gambo". Ford gave a performance at Spring Gardens in 1761, "English airs". accompanying herself on the musical glasses. She also wrote a published work, "Instructions for Playing on the Musical Glasses". The instrument was comparable to the glass harp of Richard Pockrich consisting of individual glass goblets tuned with water, and preceded the 1761 mechanized armonica (Glass harmonica) invention of Benjamin Franklin and played by Marianne Davies. Ford's accomplishments risked being complicated by an infatuated lover, the
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