""A Treatise Of The Natural Grounds, And Principles Of Harmony"" is a book written by William Holder in 1731. The book is an in-depth exploration of the principles of harmony and the natural grounds on which they are based. Holder delves into the mathematical and physical aspects of music, discussing the relationships between intervals, scales, and chords. He also examines the role of the human ear in perceiving harmony and the ways in which different...