Descant
the addition of a part or parts to a tenor or subject. This art, the forerunner of modern counterpoint and harmony, grew out of the still earlier art of diaphony or the organum. It may be said to have come into existence at the end of the 11th or beginning of the 12th century. Originally, as had been previously the case with diaphony, it consisted of two parts only, but later in its life developed into motetts and various other forms of composition. The real difference between diaphony and DESCARTES descant seems to have been that the for mer was rarely, if ever, more complimore compli cated than note against note, whereas descant made use of the various proportionate values of notes. Double descant is where the parts are contrived in such a manner that the treble may be made the bass, and the bass the treble.