EXPERIMENTS AND OBSERVATIONS 65 



this angle accurately on account of the rapidity with 

 which the whole test had to be made. I was able, how- 

 ever, to diiferentiate between them with enough accuracy 

 to designate the smallest angle (about 20°) as belonging 

 to Grade I, and the greatest angle (about 100°) as belong- 

 ing to Grade VII. By fixing certain points in the environ- 

 ment, it was possible to get approximately the same angle 

 repeatedly. The time from the third to the thirteenth tap 

 was, in all cases, taken by Prof. Stumpf by means of a 

 stop-watch. The tests were taken in the following 

 order : 



Grade of inclination : I VI II II IV V VI VII 

 Time for lo taps : 5.2 4.6 5.0 5.0 4.8 4.8 4.6 4.4 sec. 



From this series it will be seen that in the case of the 

 same angle of inclination (II and VI were repeated and 

 III was omitted) the same rate obtained in the tapping. 

 In two other tests I constantly increased the angle of 

 inclination during the 15 taps, and Hans gradually 

 increased the rate of tapping accordingly. 



In a second series I had the horse tap 14, five times. 

 I myself took the time of the taps up to 7 by means of the 

 stop-watch, while Prof. Stumpf took the time of the taps 

 from 8 to 13. At 8 I suddenly bent forward a little more 

 and retained this position until tap 13. The results were 

 as follows : 



Taps 2 to 7 (Pf.) : 3.2 2.2-2.4 2.4 2.2-2.4 2.4 seconds. 

 " 8 to 13 (St.) : 2.6 2.0 2.0 2.2 2.2 seconds. 



Such good results, however, were possible only after 

 a number of preliminary practice tests had been made. 

 The experiment was especially difficult because the horse 

 was often on the point of stopping in the midst of a test. 

 This was probably due to some unintentional movement 



