על בריאת העולם ל״אOn the Account of the World's Creation 31
א׳
1[95] We must pass on to the other kind of 7th, that which is contained within the decade. It exhibits a marvellous nature, not at all inferior to that of the former kind. For instance 7 consists of 1 and 2 and 4, which have two relations making specially for harmony, the twofold and the fourfold, the one producing the diapason harmony, while the fourfold relation produces double diapason. 7 admits of other divisions besides these, in pairs like animals under a yoke. It is divided first into 1 and 6, then into 2 and 5, and last of all into 3 and 4.
ב׳
2[96] Most musical is the proportion of these numbers also: for 6 to 1 is a sixfold proportion, but the sixfold proportion makes the greatest distance that there is (in music), the distance from the highest to the lowest note, as we shall prove, when we pass from numbers to the proportion in harmonies. 5:2 exhibits the fullest power in harmonies, all but rivalling the diapason, a fact which is most clearly established in theoretical music. 4:3 yields the first harmony, the sesquitertian or diatessaron.