W. S. Rockstro 
Practical Harmony [PDF ebook] 

Whilst the greatest effort has been made to ensure the quality of this text, due to the historical nature of this content, in some rare cases there may be minor issues with legibility. As Chords are produced, by sounding, simultaneously, three or more notes selected from the Musical Scale, it is obvious, that, before we can learn how to construct a Chord, we must learn how to construct the Scale from which it is derived. A little preliminary study will render this process extremely simple.