The work of Alypius consists wholly, with the exception of a short introduction, of lists of the symbols used (both for voice and instrument) to denote all the sounds in the forty-five scales produced by taking each of the fifteen modes in the three genera (diatonic, chromatic, enharmonic). It treats, therefore, in fact, of only one (the fifth, namely) of the seven branches into which the subject is, as usual, divided in the introduction; and may possibly be merely a fragment of a larger work.
The work of Alypius is entirely, except for a brief introduction, comprised of lists of symbols used (for both voice and instrument) to represent all the sounds in the forty-five scales produced by each of the fifteen modes within the three genera (diatonic, chromatic, enharmonic). It essentially focuses on only one branch of the seven divisions into which the subject is typically divided in the introduction; and may possibly be a fragment of a larger work.