“ While the older contrapuntists were perfectly satisfied with the laws which regulated the melodious involutions of their vocal and instrumental parts, Rameau demonstrated the possibility of building up a natural harmony upon a fundamental bass, and of using that harmony as an authority for the enactment of whatever laws might be considered necessary for the guidance either of the contrapuntist or the less ambitious general composer. ”

“ And in this he first explained the distinction between two styles, which have been called the “ horizontal and vertical systems, ” the “ horizontal system ” being that by which the older contrapuntists regulated the onward motion of their several' parts, and the “ vertical system ” that which constructs an entire passage out of a single harmony. ”