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also ill the oi',i»an itself as well the Corti's arches as the loading cells 

 remain at rest. But then we must drop all the ideas, which have been 

 broadly developed during a long time, about the impact oftheciliae 

 of the hair-cells on the membrana tectoria, on the bending of the 

 ciliae, etc. Rest prevails in the system of arches and a covibration 

 of them is necessarily excluded. 



Yet the imparting of stimuli, which was supposed to be explained 

 by the co-vibration of the hairs, need not remain a mystery, if 

 attention be paid to the effect of sound-pressure. 



In a paper, entitled "the pressure of vibrations". Lord Rayleigh ^) 

 has treated a simple case, which is nearly identical with ours. It is 

 the case of a string, itself infinite, but vibrating between two rings, 

 one fixed, the other sliding. When the string vibrates the sliding ring 

 is pressed ontwaard, towards the extremity, with an a\erage force 



E 



F= — ; E being the energy of the vibration, / the length of 



the string. 



The base of the outer pillar is in the case of the sliding ring. 

 According to Retzius the pillar is one with the semi-solid cell-mass 

 of the bottom-cell ; from this cell it would originate and form a 

 whole with it. In this way at the same time an attachment and a 

 small movability in the cell-mass have been obtained. 



But the pillar is not only in juxtaposition with the tibre, but also 

 presses on it by the inertia of the large cell-masses with which it 

 is connected, as soon as the libre begins to execute movements. Hence 

 the vibrating fibre will in this place present a node and the load 

 itself will necessarily have a great influence on the conditions of 

 tension during the \ibration. 



So the pillar has a double function : 1. that of the movable ring 

 of Rayleigh, 2. that of carrier of the inertia of a damping and 

 loading mass. In its first quality it receives a pressure in the direc- 

 tion of the modiolus, a pressure which can be perfectly measured 

 by Rayleigh's formula. 



In the model this pressure can even be demonstrated. For this 

 purpose the pillars were removed and the base of the outer pillar, 

 which imparts a node to the string, was replaced by a brass lamella, 

 provided with a slit. The split lamella grips the string like a miniature 

 fork. In this way the node is preserved. As the lamella is 19,5 cm. 

 long and 0,1 cm. thick, it possesses a certain mass, which does not 

 press on the string since the lamella is placed normally to it, but 

 gives a distinct dauiping as soon as the string vibrates. 



1) Lord Rayleigh, Philosoph. Magazine (6) III. 1902, p. 33Ü. 



