Genus(525)

Genus(525) is a 12-note epimorphic scale, listed in the Scala
directory as efg3557, where it is named "Genus enharmonicum
instrumentale". I recall Euler mentioning 7-limit genera but not him
discussing them, so I think I'd better re-read him.

It can be described as a union of four tetrads, which in the mode
Scala gives are [-1 0 -1], [0 0 0], [0 1 0], [1 1 1]; and which we may
also write {1, 6/5, 7/5, 8/5}, {1, 5/4, 3/2, 7/4}, {21/20, 21/16, 3/2,
7/4} and {35/32, 21/16, 105/64, 15/8}. As listed, each tetrad has at
least one common note with the tetrad before and after it, with the
middle pair sharing {3/2, 7/4}.