and manner of elegancy for which such a composition was intended, and next of those things of which the composition consists. And thus, that neither the bare knowledge of harmony, nor of rhythm, nor of any other things that singly by themselves are but a part of the whole body of music, is sufficient to judge and determine either of the one or the other, what has been already said may suffice to prove. 34. [Now then, there being three species into which all harmony is divided, equal in the magnitude of systems or intervals and force of notes and tetrachords, we find that the ancients never disputed about any more than one; for they never troubled themselves with the chromatic or diatonic, but differed only about the enharmonic; and there no farther than about the great interval called the diapason. The further subdivision indeed caused some little variance, but they nearly all agreed that harmony itself is but one.[65]] Therefore he must never think to be a true artist in the understanding and practice of music, who advances no farther than the single knowledge of this or that particular; but it behooves him to trace through all the particular members of it, and so to be master of the whole body, by understanding how to mix and join all the divided members. For he that understands only harmony is confined to a single manner. Wherefore, in short, it is requisite that the sense and understanding concur in judging the parts of music; and that they should neither be too hasty, like those senses which are rash and forward, nor too slow, like those which are dull and heavy; though it may happen sometimes, through the inequality of Nature, that the same senses may be too slow and too quick at the same time. Which things are to be avoided by a sense and judgment that would run an equal course. 35. For there are three things at least that at the same instant strike the ear,—the note, the time, and the word or syllable. By the note we judge of the harmony, by the time of the rhythm, and by the word of the matter or subject of the song. As these proceed forth altogether, it is requisite the sense should give them entrance at the same moment. But this is certain, where the sense is not able to separate every one of these and consider the effects of each apart, there it can never apprehend what is well or what is amiss in any. First therefore let us discourse concerning coherence. For it is necessary that coherence accompany the discerning faculty. For judgment of good or bad is not to be made from notes disjoined, broken time, and shattered words, but from coherence. For there is in practice a certain commixture of parts which commonly are not compounded. So much as to coherence.