Scales, Modes
The folk-tunes of America are not, in the main, built up on scales of the diatonic major and minor systems which, as is well known, have assumed their present form under the demands of harmony; but on a modal system which grew out of melodic exigences long before harmony made its conquest of the music of western civilisation. Nor do the folk-tunes of this country make use of all the tones of even these modal scales. They often employ but five or six of the seven available tones, leaving characteristic gaps in such scales.
American folk-tune collectors have had their troubles in the interpretation of modal melodies. I have had mine. Even such a life-long student of these things as Cecil Sharp met many a knotty problem in classifying his Appalachian tunes. In view of this difficulty I called on Hilton Rufty, a thorough musician and a reliable authority in the folk-music field, to lend a hand in the modal classification of these tunes. He generously acceded to my request; and by the time my requests had ceased and before his generosity had been exhausted he had checked or corrected all my modal classifications of the tunes in this collection. In making clear Mr. Rufty’s effective and practical method of identifying the character of tunes I shall reproduce his Classification Chart and quote here his explanation of it.