Some comments on Genus 12 & 17 and the Septendene Papers
Erv saw in the 17-tone Genus a beginning point to explore and reevaluate diatonic music beyond 12 tones. While it limits modulation to only 6 keys, he expressed that this range provides modulation that furnishes the demands of many composers yet making the modulation distance possible at any relative distance.
The last 5 pages of the first document appended by the archivist. Erv mentioned that Amiya Dasgupta had observed that much present day Indian Musicians were using a 17 tone scale for playing ragas more than 22. I assume this might reflect that perspective.
The Septendene is an earlier paper that works with the same tetrachordal material in a closely but different way. Instead of modulation through 6 keys, a disjunction (9/8) is exchanged with the relative members of a tetrachord. Since Wilson designates the 614 size of steps ( 46,47,11) It seems fit to add a letter to Ivor Derreg which includes comments about the 17 tone scale and its approximation to 612 ET.
It is worth placing side by side the two 17 tone scales above to show how they differ in the exange of only one intervall.
~Comments and Questions Welcome~