A CLASSIFICATION OF GROUPS 



291 



Figure 3 differs from the preceding figures in one essential 

 manner a small rest period ensues on the completion of the 

 first 22 beats of the group which is followed by 22 more beats. 

 This interval is not of the kind called for by the instructions to 

 the observers; it occurred or was made without the knowledge 



' FIG. 2 



FIG. 3 



of observer R, and under external conditions that cannot be held 

 accountable for it. Whatever the causes for the interval, it is 

 significant that it occurs after the completion of a 22 group and 

 that it is followed by another 22 group. As it stands figure 4 

 represents a 44 group, or two 22 groups plus the small interval. 

 The interval measures at its base exactly 3 mm. The intervals 



