Masterpieces of Science 



artificial imitation of it. The idea was novel 

 and struck me accordingly, and I requested my 

 friend to prepare a specimen for me, which he 

 did. The apparatus, as finally constructed, is 

 shown in Fig. 5. The stapes [inmost of the 

 three auditory ossicles] was removed and a 

 pointed piece of hay about an inch in length 

 was attached to the end of the incus [the middle 

 of the three auditory ossicles]. Upon moisten- 

 ing the membrana tympani [membrane of the 



Fig. 6 



ear drum] and the ossiculae with a mixture of 

 glycerine and water the necessary mobility of 

 the parts was obtained, and upon singing into the 

 external artificial ear the piece of hay was thrown 

 into vibration, and tracings were obtained upon 

 a plane surface of smoked glass passed rapidly 

 underneath. While engaged in these experi- 

 ments I was struck with the remarkable dispro- 

 portion in weight between the membrane and 

 the bones that were vibrated by it. It occurred 

 to me that if a membrane as thin as tissue paper 

 could control the vibration of bones that were, 

 compared to it, of immense size and weight, why 

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