(3) The empty spaces between the elements have no conscious part to play in the experience. Even when there is a figure in the alternate space, it comes very little into consciousness as part of the repetition, yet it is alterations in these alternates which make or mar the feeling of repetition. A series may not be beautiful in itself, but if the alternates are regular, it _feels_ repeated. _Vice versa_, the units may be enjoyable in themselves, but they do not feel repeated unless the alternates are regular and conform to certain requirements. In the units lies the _meaning_ of the repetition, in the regular alternates the possibility of its expression. (4) The rhythmic character of repetition is not felt by a certain type of subject, when it goes smoothly. When a variation is made which would destroy any possible rhythm, its lack is felt, and its violation finds expression only in rhythmic terms. (5) More violation is done to a series to have the _size_ of units varied than the filling. (This corroborates previous experiments.) (6) A certain amount of ignoring and regrouping can be done by the subject. The series is not taken exactly as given, but with selective attention. (7) In a series of different elements alternating, the most prominent one is chosen for the major unit, and the others for alternates. This prominence is more influenced by _size_ than any other factor, but may be due to intrinsic interest of any kind. (8) The major and minor elements must have a certain difference from each other, both in _appearance_ and _interest_, and they must be different enough for the difference to be easily perceived, but not enough to be incongruous. They must differ in interest enough, so that one is easily more prominent than the other, or may be made subservient to the other, in the apperception. (9) Variations are pleasant in the principal unit repeated, but not in the alternating figure unless very slight indeed, or affecting only secondary parts of the figure, not the main lines. (10) Not the time actually spent on a unit makes it more or less prominent, but the feeling of more or less "energy" expended on it. _Ends:_ In an alternating repetition, must the series end on a light or heavy beat? That is, must the major or minor unit be on the end? To test this a series of strings was hung in which a group of three alternated with a single string. [Illustration: Fig. 23]