👉 Diatonicism is a musical theory that posits that musical scales are based on notes that have equal and opposite intervals. This theory was developed by German composer Felix Mendelssohn in the late 19th century. Mendelssohn's approach to diatonic music involves the use of a series of scales, each with its own set of harmonics (the "diatonic scale") that are based on the notes of the major and minor scales. These diat
