The immediate problem was: What is the relation between the width of interval used and the pleasure got by hearing the motive _a-b-a_ and _b-a-b_, where _a_ is always the lower tone. The method of procedure was to take a fixed tone (460 vibrations in the first case) and get a series of observations on successive progressions _b-a-b_ where _a_ differed from _b_ by 4, 8, 12 ... 56 vibrations. The greatest difference thus is approximately a musical whole tone. Then a series of observations was taken on _a-b-a_ where _a_ similarly differed from _b_ by 4, 8, 12 ... 52 vibrations. The progressions were given in irregular order, that there might be no chance of the observer getting into a fixed habit of replying. The intimate relation between the pleasure in successive musical tones and the pleasure in musical harmonies suggested naturally the question whether the feeling-value of these unmusical progressions was not somehow dependent upon the affective character of the simultaneous presentation of the same tones. Therefore after a progression had been given once and judgment recorded, the two tones used were given as a "harmony," that is simultaneously, and a judgment taken as to its agreeableness. This was immediately followed by the same progression, thus giving opportunity to observe the relation between the feeling-tone of the interval as it appeared in successive and in simultaneous presentation. The results of this part of the investigation are graphically represented in the following plates. Tables I and II indicate the feeling-value of _a-b-a_ where _a_, the lower tone, is 460 vibrations, and _b_ is from 4 to 56 vibrations in addition, and the feeling-value of _b-a-b_ where _b_, the higher tone, is 460 vibrations and _a_ is from 4 to 56 vibrations less. [Illustration: PLATE VI.] The base-lines from which the vertical lines to the curves are drawn represent the feeling-tone 4, the indifference-point. Above comes 3, 2, 1 and below 5, 6, 7; each square represents a unit. The horizontal abscissæ represent the width of the interval; the arrows indicate the musical intervals. The observers are given by initials. The first evident fact for both average curves of Plate V is that the maximum pleasure does not coincide with a musical interval, but comes with an interval four or eight vibrations less than either the half or the full tone of the musical scale. While in both cases the first elevation of the curve comes before the semi-tone, _b-a-b_ shows a decrease of pleasure as the whole step is approached while _a-b-a_ rises again. The order _a-b-a_ is liked better than _b-a-b_.