Septendecimal

If it is desired to proceed beyond tertian to septimal harmony to introduce the harmonic form of the phord of the dominant Seventh, with the ratios 4 : 5 : 6 : 7 as Mr. Poole has done (see sect. F. No. 7), or even to septendecimal harmony to introduce the harmonic form of the chord of the minor Ninth 8 : 10 : 12 : 14 : 17 (see p. 346c, note *), the number of the notes will be nearly tripled. […] The cents in the tertian chord of the minor Ninth C E, G B♭ D¹♭ are 0, 386, 702, 996, 1200 + 112. Hence the cents in the harmonic septimal chord of tiie dominant Seventh, or C E₁ G B♭, are 0, 386, 702, 969, and the cents in the septendecimal chord of the minor Ninth, or C E₁ G ⁷B ¹⁷D¹♭, are 0, 386, 702, 969, 1200 + 105.

I am sorry I cannot illustrate septendecimal harmony on this instrument as it is now tuned. It does not go beyond septimal harmony.

17/8 septendecimal minor ninth / 17/12 2nd septendecimal tritone […] 24/17 1st septendecimal tritone