42 UNIVERSITY OF MISSOURI STUDIES 



at A : and the partition has the same position which it had 

 then. We have thus graphically represented the characteristic 

 positions through which the partition passes during a com- 

 plete period of the movement in question. 



The graphic representation, of course, is only a means 

 to an end. We have to read off from this representation 



how many shocks are received during the 

 How to read off period by the nerve ends on each section 

 the tones heard °f the partition. This is easily done. Let 

 and their us again, for want of definite knowledge, 



intensities make the assumption that a jerk down of 



the partition means a stimulation of the 

 nerve ends, and that a jerk up is irrelevant. We then sim- 

 ply have to go down in the figure from the top to the bottom 

 and count the number of times each section is jerked down. 

 The first section is down at P., up again at C, down for a sec- 

 ond time at D, up again at E, down for a third time at F, 

 and up again at G. The nerve ends on this section, there- 

 fore, receive three shocks during the period. We find the 

 same number of stimulations on the following five sections. 

 Let us now inspect the seventh section. It is down at B, up at 

 C and still up at D and E. It is down for a second time 

 at F and up again at G. That is, the nerve ends on this sec- 

 tion receive two shocks during the period. The same is true 

 for the following twelve sections. Let us now look at the 

 twentieth section of the partition. It is down at B, still down 

 at C, D, E, and F; up again at G. That is. the nerve ends here 

 receive only one shock during the period. The same holds 

 for the following ten sections. We see, then, that three 

 tones must be simultaneously heard, which we may call, 

 according to the relative frequency of stimulation, the tones 3, 

 2, and 1. The relative intensities of these tones may be re- 

 garded — under the provisional assumption of a uniform dis- 

 tribution of nerve ends lengthwise over the partition — as six, 



