color organs

During the 1730s Pierre-Louis Castel , a Jesuit priest influenced by Newton's Optics, devised a clavecin oculaire, called color organ in English, and constructed a model later in the decade; by depressing a given key, a pallet was opened, and not only did sound issue from the corresponding pipe, but its complementary color appeared simultaneously in ribbon form, for the seven colors of the spectrum were made to correspond to the seven tones of the octave. Diderot , in an undated...