psychological and aesthetical aspects. The topic is far too intricate and unsettled for discussion here, yet two or three points may be noted in passing. lVe are not specially concerned with objective rhythms, recurring series of impressions—that is to say, in which there are actually periodic variations of intensity, interval and the like. What is remarkable is that even a perfectly regular succession of sounds (or touches), qualitatively and quantitatively all alike, a series therefore devoid of all objective rhythm, is nevertheless apprehended as rhythmically grouped, provided the rate lies between the limits of about 0-8” and 0~I4”. The slower of these rates leads to simple groups of two, replaced by groups of four or eight as the rate increases; groups of three and six also occur, though less frequently. The average duration of the groups, whether these are large or small, is comparatively constant, measuring rather more than one second. The subject usually keeps time by taps, nods or other accompanying movements; the pulse and respiration are also implicated. These organic rhythms have even been regarded as the prime source of all psychical rhythm and of its manifold aesthetic effects. Some Connexion there is unquestionably. As the decimal system corresponds to our possession of ten fingers, and our movements to the structure of our limbs, so here we may assume that physiological processes fix the limits within which psychical rhythm is possible, but yet may be as little an adequate cause of it or its developments as fingers are of arithmetic, or legs of an Irish jig. In motor rhythms, such as the last, the initiative is obviously psychical, and the respiratory and other periodic organic processes simply follow' suit. And even sensory rhythms can often be varied at the subject's own choice, or on the suggestion of another; and then again the breathing is altered in consequence. Familiar instances of such procedure are to be found in the “ tunes ” so readily attributed to the puff of a locomotive, to the churning of a steamer's screw, and the like. Psychical rhythm, then, we may conclude, is due to attention or apperception, but the conditions determining it are many, and their relations very complex. If the presentations to be “ rhythmized " (the rhylhmizomenon, as the Germans say) succeed each other slowly, the length (or shall we say the breadth?) of the “ psychical present” tells one way: the first impression is below the threshold when the third appears. If they arrive rapidly, their intensity and duration and the span of pretension tell another way; for it is essential that they retain their individual distinctness and only so many can be grasped at once. But if the series continue long enough, or be frequently experienced, sub-groups may be treated as individuals; and indeed till some facility is acquired, the subject attending is aware of no rhythm. In the act of attention itself there are phases, in so far as expectation involves readjustment to what is coming: usually the first members of a tact are predominant, and the rhythm tends to “ fall ”; several alternations of accent within a complex rhythmic whole are of course still compatible with this. But it is important to note that, whether simple or complex, the rhythm is an intuited unity as truly as a geometrical figure may be. Unlike a geometrical figure, however, it rarely or never has symmetry. We cannot reverse a tune and obtain an effect comparable with that obtained by reprinting the score backwards in line with the original. We now pass to a question in which the psychological bearing of this fact becomes apparent! But first a new method of dealing with memory-problems must be mentioned, in which the connexion between rhythmizing and memorizing has been turned to account by the Gottingen psychologists. The method of Ebbinghaus consisted in ascertaining the repetitions saved in consequence of previous repetitions, when the verse was relearnt some fixed time later. Hence this method is called the learning method or the method of saving. When, a given time after a certain number of repetitions (say) in trochaic measure, the subject is confronted with one of the accented syllables and asked to name the unaccented syllable that belongs to it, he will answer sometimes rightly, sometimes wrongly, and sometimes be unable to answer at all. This, the new, method is therefore named Trejfer-methods, the method of “ shots, " or, let us say, the telling method. It enables the experimenter to obtain far more insight into details than was possible before, for the “ misses " as well as the “hits” are instructive. Moreover, by measuring the time of each answer~(T$'ejcrzeit) and comparing these times together, much can be learnt; in stronger or recent associations, for example, the answers being quicker than in weaker or older ones. Does association work forwards only or backwards also, as the middle link of a chain, when lifted, raises the contiguous links on either side of it? This is certainly not the case when the forward direction makes sense, but with nonsense verses, if the mechanical analogy is a sound one, such reversal is to be expected. For here there are none of the “ obstructing associations ” which The following are among the more important papers on rhythm: T. L. Bolton, “ Rhythm, " Am. Journ. of Psychology (1894), pp. 145 sqq.; E. E. Meumann, “ Untersuchungen z. Psychologie u. Aesthetik des Rhythmusf' Phil. Studien (1894), x. 249 sq ., 393 sqq.; M. K. Smith, “ Rhythmus und Arbeit, " Phil Sludien (RIQOO), xvi. 71 sqq. 197 sqq.; Arbeit und Rhythmus (1899), by K. Bucher, a well-known economist, bringing out the teleological aspects of rhythm. “ rhyme and reason” imply. In learning a verse backwards Ebbinghaus found a saving of 12~4 % of the time originally taken up in learning it forwards. A saving almost as great (1o~4 %) was effected by relearning a like verse forwards, but skipping one syllable: the order of syllables, that is to say, being r, 3, 5, 15, 2, 4, . . . 16. Even when learning backwards and skipping one syllable, Ebbinghaus found a saving of 5 %. But the number of his experiments (four) was too few to give this result much value, as he fully admits. These experiments as a whole, then, might incline us to suppose that association does work in both directions, though the Connexions backwards are considerably weaker. But if so the associations both ways should be alike at least in form-continuous, that is to say, backwards, d c b a, as well as forwards, a b c d. The facts at present available are, however, against this. In two or three hundred experiments by Müller and Pilzecker, verses of twelve syllables were repeated a set number of times in anapestic measure -accented, that is to say, on the 3rd, 6th, 9th and 12th. After a fixed interval the subject, confronted with one of the accented syllables, mentioned any of the other syllables which he called to mind. Now the cases in which the syllable immediately preceding was revived were only about half as frequent as those in which the syllable next but one preceding was revived; the time of telling (Trejerzeit) for the latter was also shorter. This result is incompatible with the theory of continuous backward association, but it is readily explained by the fact that the group of three syllables had become one complex whole, and it shows that the tendency to reinstate the initial member of the group is stronger than that to reinstate the middle. The saving effected in Ebbinghaus's experiment is also thus explained? A somewhat paradoxical situation is brought to light when the method of saving and the method of telling are used together. In the experiments by ]ost, mentioned above, the series of verses were repeated thirty times; after an interval of twenty-four hours one series was tested by the first method and the other by the second. Two new series were then taken: the first repeated four times, and after an interval of a minute tested by the first method; the other was then repeated in like manner, and tested after the same interval by the second method. The old series was found (by the method of saving) to require on an average 5-8 5 repetitions for relearning, and the new 9-6; yet on the method of telling, the new series yielded 2-7 “ hits, ” with an average time of about 1% second for each, while the old yielded only -9 “ hits, ” with an average time of 4% seconds for each. Thus one may be able to reproduce relatively little of a given subject matter, and yet require only a few repetitions in order to learn it off anew; on the other hand, one may know relatively much, and still find many more repetitions requisite for such complete learning. The “age ” of the associations is then important. Other things being equal, we may conclude that each fresh repetition effects more for old associations than for recent ones. It might be supposed that the strength of the old associations was more uniform and on the average greater than the strength of the new; so that while none of the old were far below the threshold, few, if any, were above it; whereas more of the new might be above the threshold though the majority had lapsed entirely. And the latter would certainly be the case if the subject of experiment tried to make sure of a few “ hits, ” and paid no attention to the rest of the series. Due care was, however, taken that the ends of the experiment should not in this way be defeated. Also, there is ample evidence to show that the supposed greater uniformity in strength of old associations is not, in fact, the rule. We seem left, then, to conjecture that the difference is the effect of the process of assimilation working subconsciously-that psychical aspect of nervous growth which Professor Tames has aptly characterized by saying that “ we learn to skate in summer and to swim in winter.” It continually happens that we can recognize connexions that we are quite unable to reproduce. To the diminished “ strength” of an association, as tested by the 2There are still other forms of what seems at first sight to be regressive association, but none that do not admit of explanation without this assumption.