On page 100 in Henry Cowell's book (PDF here) there is an explanation centered around C-C#
(C#) contained with in a whole note has four and two-seveths vibrations per second and it will be found that a seven-thirtieths note, which is the corresponding time-value of (C#) will be contained in a whole note four and two-sevenths times , in other words, four seventh-thirtieths notes...
What is a seven-thirtieths note? how does it relate to this Ratio (14:15)?