MECHANICS OF THE INNER EAR 9 1 



spreading of the displacement lengthwise over the partition. 

 At III the velocity of the stirrup is still greater than at II. 

 Therefore we notice again a slight increase in the displace- 

 ment of the initial part of the partition. But as the stirrup 

 approaches F, this increase of displacement of the initial parts 

 must become less ; for the velocity of the stirrup is now nearly 

 constant, its increase very slight, and the increase of displace- 

 ment is in any case much less than proportional to the increase 

 of velocity, according to figure 27. As soon as the stirrup passes 

 F, its velocity begins to decrease. Immediately the press- 

 ure on the whole piece of the partition which has yielded de- 

 creases; and this whole piece, therefore begins to move 

 slowly back by its elasticity in the direction of its normal 

 position. It is clear, however, from figure 27 that even a 

 considerable decrease of the velocity of the stirrup causes only 

 a slight decrease of the displacement until the stirrup ap- 

 proaches G, when its velocity approaches zero and the part 

 of the partition in question can move more rapidly by its 

 elasticity since it has no longer to overcome much pressure 

 caused by the stirrup. It does not follow, however, that any 

 point of the partition has returned to its normal position by 

 the time the stirrup reaches G. The initial sections have 

 merely moved in the direction of their normal position. And 

 meanwhile, new points of the partition to the right must 

 have yielded upwards to make room for the fluid being dis- 

 placed all the time by the stirrup in moving towards G. 

 Three positions of the partition between F and G are shown 

 in figure 28 at IV, V, and VI. 



