along definite lines, arousing and fulfilling definite expectations. Those forms of modernist music that dispense with scales altogether, in which therefore there are no fixed _points de repere_ like the tonic or dominant of the older music, can express chance momentary moods by means of rich and strange colors, but not an orderly and purposeful experience. Of course, in our modern harmonic music the melodic movement proceeds by means, not of single tones, but of chords. Yet no new principle is introduced by this fact. For the chords have in part merely the significance of highly enriched tones, the harmonized tones of the chords taking the place of the partials of the single notes and imparting a more voluminous color, which may have its own beauty as such; and, in addition, they simply confer upon the melody another dimension, as it were, the tonal relations of harmony and contrast operating between the tones of the chords simultaneously, as well as temporally between the successive elements of the melody. The orderly beauty which the tonal relations confer upon music is further enriched and complicated by rhythm. Rhythm in music is of two sorts: a rhythm of time and a rhythm of accent, or increased loudness. Through the one, the duration of a musical composition is divided up into approximately equal parts filled by notes and rests of definite length, and through the other, the light notes are subordinated to the heavy notes. The two, however, are interrelated; for the bars are divided from each other by the accents, and the accents recur at approximately equal intervals. The pleasure in rhythmical arrangement is derived from two sources: first, from the need for perspicuity which is fulfilled through the regular grouping of the tonal elements in the bars,--their length being adjusted to the average length of an attention wave, and the number of tones that fill them to the number of items which can be taken in at one act of attention,--and through the subordination of the light to the heavy within the bars, the bars to the measures, and the measures to the periods. The second source of satisfaction in rhythm is the combination of feelings of balance and harmony aroused--a rhythm is not only a pleasing perspicuous order, but an emotion. [Footnote: See chap. V, p.90] For every recurring accent and interval competes with its predecessor for the mind's attention, yet is in agreement with it since it, too, fulfills the law that pervades them all.