This will be apparent, if any one shall examine every one of the parts, and see what is the subject of their several contemplations. For harmony takes cognizance of intervals, systems, classes of harmonious sounds, notes, tones, and systematical transmutations. Farther than this it goes not. And therefore it would be in vain to enquire of harmony, whether the poet have rightly and (so to speak) musically chosen the Dorian for the beginning, the mixed Lydian and Dorian for the end, or the Hypophrygian and Phrygian for the middle. For the industry of harmony reaches not to these, and it is defective in many other things, as not understanding the force and extent of elegant aptness and proper concinnity. Neither did ever the chromatic or enharmonic species arrive to such force of aptitude as to discover the nature and genius of the poem; for that is the work of the poet. It is as plain, that the sound of the system is different from the sound of the descant sung in the same system; which, however, does not belong to the consideration of harmonical studies. There is the same to be said concerning rhythms, for no rhythm can claim to itself the force of perfect aptitude. For we call a thing apt and proper when we consider the nature of it. The reason of this, we say, is either a certain plain and mixed composure, or both; like the enharmonic species of Olympus, by him set in the Phrygian mood and mixed with the paeon epibatos, which rendered the beginning of the key naturally elegant in what is called the nome of Minerva. For having made choice of his key and measure, he only changed the paeon epibatos for the trochee, which produced his enharmonic species. However, the enharmonic species and Phrygian tone remaining together with the whole system, the elegancy of the character was greatly altered. For that which was called harmony in the nome of Minerva was quite another thing from that in the introduction. He then that has both judgment as well as skill is to be accounted the most accurate musician. For he that understands the Dorian mood, not being able withal to discern by his judgment what is proper to it and when it is fit to be made use of, shall never know what he does; nay, he shall quite mistake the nature and custom of the key. Indeed it is much questioned among the Dorians themselves, whether the enharmonic composers be competent judges of the Dorian songs. The same is to be said concerning the knowledge of rhythm. For he that understands a paeon may not understand the proper use of it, though he know the measure of which it consists. Because it is much doubted among those that make use of paeons, whether the bare knowledge make a man capable to determine concerning the proper use of those rhythms; or, as others say, whether it aspire to presume so far. Therefore it behooves that person to have two sorts of knowledge, who will undertake to judge of what is proper and what improper; first, of the custom 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. [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. The passage in brackets is out of place here, and is generally transferred to the middle of Chapter XXXVII. (G.) ] 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. 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. We are next to consider whether the masters of music are sufficiently capable of being judges of it. Now I aver the negative. For it is impossible to be a perfect musician and a good judge of music by the knowledge of those things that seem to be but parts of the whole body, as by excellency of hand upon the instrument, or singing readily at first sight, or exquisiteness of the ear, so far as this extends to the understanding of harmony and time. Neither does the knowledge of time and harmony, pulsation or elocution, or whatever else falls under the same consideration, perfect their judgment. Now for the reasons why a musician cannot gain a perfect judgment from any of these, we must endeavor to make them clear. First then it must be granted that, of things about which judgment is to be made, some are perfect and others imperfect. Those things which are perfect are the compositions in general, whether sung or played, and the expression of those, whether upon the instruments or by the voice, with the rest of the same nature. The imperfect are the things to these appertaining, and for whose sake they are made use of. Such are the parts of expression. A second reason may be found in poetry, with which the case is the same. For a man that hears a consort of voices or instruments can judge whether they sing or play in tune, and whether the language be plain or not. But every one of these are only parts of instrumental and vocal expression; not the end itself, but for the sake of the end. For by these and things of the same nature shall the elegancy of elocution be judged, whether it be proper to the poem which the performer undertakes to sing. The same is to be said of the several passions expressed in the poetry.