8o 



UNIVERSITY OF MISSOURI STUDIES 



the partition. Imagine further that the quantity of displaced 

 fluid for the tone A is 20 per cent of the total amount of fluid 

 displaced by the compound sound wave, that the quantity 

 for B is 50 per cent, and the quantity for C 30 per cent. This 

 is a percentage which might easily be found in an actual case. 

 The pitch of the tones A, B, and C is irrelevant. The table 

 below contains all the values wlhich are of interest to us, for 

 two cases. In the first case the actual fluid quantities are 

 two, five, and three, by assumption; in the second case they 

 are ten, twenty-five, and fifteen. That is, the stirrup move- 

 ment in the second case is of the same form, but exactly five 

 times as large as in the first. 



The table shows that the tone intensities do not increase 

 proportionally to the increase in the amplitude of stirrup move- 

 ment. The amplitude in the second case is five times that of 

 the first case ; but the total intensity (S) of the audible sound 

 in the second case is less than twice that of the first case (50.0 

 compared with 35.3). The table shows further that the inten- 

 sity of the tone A is in the first case 44.7 per cent, in the second 

 case 50.6 per cent. That is the increase in the intensity of the 

 whole sound is favorable to the relative intensity of the tone 

 produced by the initial section of the partition. The percentage 

 intensity of this tone, A, is increased at the cost of the tones 

 B and C, the percentages of both of which are diminished. 



