24 UNIVERSITY OF MISSOURI STUDIES 



relations existing between all the several movements. Only 

 thus can we obtain a definite view concerning the nervous 

 stimulations received by the brain as the result of a given 

 rhythmical movement of the stirrup. In order to find the 

 movements of the partition in every detail we might try com- 

 putation since this is the method wihich yields, although not 

 always the clearest, yet in general the most accurate results. 

 Our chief task, then, would be, stated again as definitely 

 as possible, to find out for each point of the partition which 



moves at all the exact time which elapses 

 Computation of from a jerk down to a jerk up and from 

 the form of a jerk up to a jerk down. Figure 9 may 



motion of the help us to understand the conditions of 



partition computing the time interval in question. 



Let us call x the distance of any point of 

 the partition from' the point of x^ nearest the windows. The 

 length of the part of the partition which moves in response 

 to the motion of the stirrup depends, of course, on the ampli- 

 tude of the movement of the stirrup. This length alone is 

 represented in the figure. What is farther to the right re- 

 mains motionless. The dotted lines above and below rep- 

 resent the upper and lower limit of each moving point of 



<(W 



Fig. 9. The partition in the tube and its 

 limits of movement 



the partition. In our curve, figure 8, the minimum, at A, rep- 

 resents the position of the stirrup most to the left, the max- 

 imum, at the time B, the position of the stirrup most to the 

 right. The horizontal line represents, of course, the time. To 

 the position of the stirrup at A corresponds the position of the 

 partition (in figure 9) in its upper limit; to the position of 



