122 THE HORSE OF MR. VON OSTEN 



ments, — all translated through the workings of the levers 

 into up-and-down movements. The objective direction of 

 these head movements is indicated by the arrows. It will 

 be noted that (because the lever in question was one 

 with two arms, and therefore reverses all movements 

 made) each lowering of the head of indicated by a rise in 

 the fourth curve, and each raising is the head is recorded 

 by a sinking in the same curve. The records of the head 

 movements forward and backward and to the left and 

 right (curves 2 and 3) are two and one-half times the 

 size of the actual movements; while the curve of the 

 movements up and down (curve 4) — which is of especial 

 interest to us — is five times its actual size. The fifth 

 and sixth curves, which record my own responses, 

 represent the taps of the horse, — the fifth indicating the 

 number of taps and the sixth the back-step, which was 

 Hans's reaction when he noted the head- jerk of the 

 questioner. The seventh, the lowest line, indicates the 

 time in fifth-seconds. Since the rate at which the drum 

 revolved was not uniform for all the tests, the fifth- 

 second marks do not appear the same distance apart in 

 all the records, but are farther apart the greater the 

 rapidity with which the drum revolved. For the experi- 

 ment itself this is quite immaterial. Figures 6 to 9 cor- 

 respond in detail with the diagram just described. 

 Figures 10 to 12 differ only in that the breathing and 

 back-step curves (the first and sixth in the diagram) are 

 lacking. In these there is no response on my part to 

 the head-jerk of the subject, but tapping was continued 

 ad libitum (in the case of the illustrations here given I 

 tapped to 5). When these latter curves were taken the 

 ordering and the technique of the experiments had not 

 yet been perfected. When this was finally done, Mr. 



