Note 6 — Art. I. Essay on Musical Temperament.
Reading edition
The propriety of making 25 : 36 the true ratio of the 5th will be manifest, when it is considered that this is the value of that interval as sounded by voices and perfect instruments; when the 3ds which compose it are made perfect. This interval, as found in the scale which has the fewest tempered concords possible referred to at the beginning of this essay, ought to be regarded as the true 5th, flattened by a comma, in the same manner as one of its component 3ds will be allowed by all to be flattened.