affecting consciousness at the moment are bound to the preceding ones that have retreated into the darker regions of consciousness, and, on the other hand, they are preparing the way for further expected impressions. The chief difference of the two cases lies not so much in the formal relations of the scope of attention and of consciousness, as in the constitution of the elements and their combinations. Let us now, equipped with the results of our visual experiments, turn our attention again to our metronome experiments. The analogy between the two immediately gives rise to this question: Can we not in our rhythm experiments arrange the conditions so that we may obtain a similar isolation of simple impressions, as was necessary in measuring the scope of attention for the sense of sight? Now in fact such an isolation of single beats arises at once, as soon as we restrain a "hearing into" the beats of any kind of accentuation whatever. Even the simplest rhythm, the 2/8 time, must be avoided. This is not so easy as it appears to be at the first glance, because of the rhythmical disposition of our consciousness and of our whole psycho-physical organisation. Again and again we are inclined to hear into a row of beats following each other at similar intervals, at least the 2/8 time. And yet it is possible to conform to this condition, if the metronome beats do not show any noticeable objective differences. The interval between the beats must be chosen long enough to check any tendency to rhythmical grouping, and yet not too long, so that it may still remain possible to grasp so many beats as one whole. In general an interval of from 1 1/2-2 1/2 seconds will conform to this requirement. With such an interval, after a fair amount of practice, it is possible to change at will from a rhythmical to an unrhythmical or absolutely monotonous perception of the beats. If this is done, and if in exactly the same manner as in the rhythm experiments a number of metronome beats is given, and then after a pause the same or a slightly differing number is given, the observer can clearly perceive the identity or difference of the two rows. If in the first test a row of six beats is given (row A), and in the second a row of nine, it appears in repeating two rows of the same length, that a precise recognition of identity is present with row A, whereas with row B this is impossible. Even with seven or eight beats recognition is very uncertain. We arrive therefore at the same result as in our optical experiments. Six simple impressions form the limit for the scope of attention. [Illustration row A - row B]