In music and tuning, the ragisma is an interval with the ratio of 4375:4374, ≈0.396 cents (a superparticular ratio). It is usually defined as the difference between the septimal minor third (7:6) and two Bohlen–Pierce small semitones (27:25 Play one (help·info)). It is also the difference between minor Bohlen–Pierce diesis (245:243) and septimal semicomma (126:125), as well as the difference between the septimal third tone (28:27) and the greater diesis (648:625). ( Play (help·info))
- Haluska, Jan (2003). The Mathematical Theory of Tone Systems, p.xxviii. ISBN 80-88683-28-9.