MODES (OR, Fr. mode, from T.:it. tannins, measure, manner). The octave species in use before the time of the invention of harmony as well as during the period of the contrapuntal style up to the lime of Hach. The original scale of the ancient Creeks was a minor sole with semi-steps between the third and fourth and seventh and eighth degrees. Other tones than the fmalament:t1 were also taken as starting points, but the tones of the original scale remained unaltered. This shifted the position of the semi-steps every time the starting tone was shifted. The eon:Ideal thins of t ones hots old a hied were regarded as separate scales and called oc tave species. This system the theorists of the early Aliddle Ages adopted. lint instead of using desrendina settles they made use of tine, tiding At the same time 'they retained the original Creek 111t1114,i, lint applied them to scales not corresponding to the original Creek scales. From among the nine octave species of the Creeks four were originally selected for the serviee of the ehureh. These were known 114 the authentic modes. Their establishment is commonly at tributed to Saint Ambrose, Bishop of Milan. who ( In this table the final note, corresponding to our modern tonic, of each mode is indicated by a half note, the semi-steps by slurs.) It will he seen that the compass of every authentic mode is from the final to its octave above: that of every playa! mode from a fourth below to a fifth above the final. Every authentic mode has its corresponding /dorm/ distinguished by the prefix hypo (under). and beginning a fourth below the authentic mode. Furthermore. every mode must he eonsidered as consisting of two series of tones forming either a pentaelmrd or a tetrachord in such a manner that the highest lone of the lower series is at the same time the lowest of t he higher series. In the authentic modes the first live tones constitute the pentachord. the last four the tetraehord. In the plagal modes the tetraehord comes before the penta eltord. The former arrangement is called by the eminent theorist Zarlino (9.v.) harmonic di vision (dirisione armonien); the latter rya nge ini.nt. arithmetical dirision (dirisione metiral. la examining the above table it will he noticed that the pentaehords tetrachords of all the modes, except the Uteri:in and Tlypo loerian, exhibit the compass of a perfect fifth or fourth. In these two modes the peutachord represents the compass of a diminished fifth. the tetrachord that of an augmented fourth (trito nus). Both these intervals were strongly con demned by musical theory, and hence these two modes were rejected as impure, and therefore impracticable.
In every mode four notes have a special sig nificance, just as the tonic. dominant, and sub dominant have in our Modern scales. These notes are: (1) The final; (2) the dominant; (3) the mediant ; (4) the participant. The final is the tone on which every melody ends. By means of this tone the mode in which any melody is written is determined. If it moves within the range of the final and its octave, the mode is authentic; if it moves below or above the final, the mode is plagal. The dominant of every
authentic mode is found a fifth above the final; of every plagal mode a third below the dominant of its corresponding authentie mode. The only tone which can never serve as a dominant is B. Whenever B would occur, C is substituted for it. The reason for this change is that B always forms a dissonant interval with F. either an aug mented fourth or a diminished fifth. The me diant derives its name from the fact that in the authentic modes it always lies midway between the final and the dominant; it is always the third tone of the mode. In the plagal modes the position of the mediant is rather unsettled, owing to the necessity of obtaining a convenient tone for cadences, as in the case of the dominant, and for the same reason B can never appear as a mediant. C is invariably substituted. The participant in the authentic modes lies either between the final and the mediant. or between the mediant and the dominant. If. however, two notes lie between the mediant and the dominant, either tone may serve as the par ticipant. In the plagal modes the participant is always the same as the dominant of the cor responding authentic mode. Since each plagal mode begins a fourth below its corresponding authentic. this dominant (participant of the is the same as the lowest tone of the plagal mode. Here, again, B is barred and C substituted. Likewise F can never be partici pant, the next higher tone (G) being substituted.
While every melody must end upon the final, it may begin upon any one of the four just-men tioned tones. But ant' phrase except the last of a melody may also end upon these tones. Renee they are also called cadences or modula tions. As in a long melody a feeling of monotony would be produced by the constant employment of these modulations, two or more tones are ad mitted. The final. dominant, mediant, and par ticipant are called regular modulations, and the additional tones conceded modulations. One of the most frequent of these conceded modulations is the seventh tone of the mode. This always appears an octave lower than the true pitch, on account of a license permitting the extension of every authentic mode by one tone below its final and of every plagal mode by a sixth above the final. In order to bring melodies within the range of certain voices it sometimes happens that they are written a fourth higher or a fifth lower than the regular mode. Such trans position is always indicated by a B flat in the signature. In these _cases the true final will be either a fourth below or a fifth above the closing note.
..\ecording to their range melodies are classed as perfect, imperfect, and superfluous. A perfect melody moves within the range of the mode in it is written; an imperfect melody does not exhaust the entire range; a superfluous melody exceeds the range either above or below. Some melodies exhaust the complete range of both the authentic and its corresponding plagal Mode; these are said to be written in a mixed mode. See CnEEK Stowe: PLAIN CHANT; and for an explanation of the two modes in use at present, see MAJon; Mixon.