500 IRVING HARDESTY 



external meatus but could not be allowed to touch it during the 

 experiments. Trumpets such as the cornet, held in the hand, 

 were merely directed into the meatus. 



The external meatus with the tympanic membrane had to be 

 mounted upon a heavy w^ooden block (WB, fig. 5, A) and even 

 then it was found necessary to brace it against a cleat fastened 

 upon the table, for certain vibrations of low frequency would 

 cause it to move gradually away from the ossicle pressed upon 

 the membrane. 



The adjustment of the distance between the copper plates and 

 the ends of the platinum wires during the experiments was made 

 to the point at which the least movement of either plate or wire 

 would make or break the electric current. Usually a position 

 just at the brink of the make of the current was employed. This 

 could be determined by observing the vibrator of the signal- 

 marker while manipulating the adjustment screws, the battery 

 being interposed. 



RESULTS 



It was realized that an apparatus so infinitely larger, heavier 

 and coarser in construction than the mammalian auditory 

 apparatus could not be expected to give many results trustworth- 

 ily representing the behavior of the actual apparatus. Many 

 of the apparent phenomena with the model were so confused 

 and seemed so complex that no attempt will be made to describe 

 them on the ground that they were more the result of imper- 

 fections in the model than representing behaviors of the normal 

 apparatus. Interpretations of only the few simpler results will, 

 be undertaken and these interpretations will be limited. 



I have described the construction of the model in considerable 

 detail with the hope that its repetition with the possible improve- 

 ments, may be suggested to other investigators and that the 

 experuTients may be repeated and extended. 



Of the results given by the model indicating the action of the 

 tectorial membrane, the following are considered most directly 

 suggestive. 



