456 Prof. More and Dr. Fry on the Appreciation 



behind and 180° in front. When the experiments were made, 

 the order of changing the lengths of the tubes was entirely 

 arbitrary, that is for a given observer the two tubes might 

 be equal for the first observation, then the right tube might 

 be lengthened a half wave-length, or the left tube be 

 lengthened a quarter of a wave-length and so on. 



Fitch of fork = 512. 



Table I, 



Wave-length (A) = G4 cm. 





50=0. 



0(f) =i\. 



iX. 



|X. 



*x. 



| -A . 



fA. 



fX. 



X. 



A... 



o 



U 



o 



225 



o 



6/5 



o 



07'5 



Q~ro 



o 

 90 



o 



90 



67 5 



] 67-5 



B... 







22-5 



45 



675 



90 



67"5 



90 



67-5 



45 



C ... 











22-5 



45 



45 



67 - 5 



90 



67-5 



67-5 



D... 







22 5 



22-5 



67-5 



67-5 



90 



45 



45 



07-5 



E ... 







225 



G7-o 



07-5 



45 



67*5 



45 



6ro 



67 5 



F ... 







22-5 



45 



67 5 



90 



675 



G7 - 5 



67'5 



90 



G ... 







22o 



22-5 



45 



67 5 



90 



45 



22-5 







H... 







22-5 



45 



07 '5 



67-5 



225 



90 



90 



90 



I ... 







22-5 



45 



675 



90 



67-5 



90 



90 



1125 



K... 







22-5 



675 



90 



67*5 



45 



67'5 



45 



90 



Fitch of fork = 320. 



Table II. 



Wave-length (X) = 104 cm. 





#0=0. 



S0=IX. 



*x. 



!*■ 





fX. 



fX. 



|X. 



X. 



L ... 



C 







o 

 225 



o 

 45 



o 

 45 



o 



90 



i 90 



o 

 90 



90 



90 



M... 







22-5 



45 



67-5 



67-5 



67-5 



90 



90 



90 



N ... 







22-5 



90 



90 



90 



' 90 



90 



67-5 



90 



O ... 







22-5 



675 



45 



22 5 



67-5 



90 



90 



90 



C ... 





225 



45 



67 5 



90 



90 



90 



90 



90 



F... 







45 



07-5 



67-5 



67-5 



67*5 



67-5 



67-5 



90 



I ... 







22-5 



45 



67'5 



67 5 



90 



90 



90 



90 



In spite of a certain indefiniteness in the results and con- 

 siderable variations in the exact direction for any given 

 phase-difference, the observations of these fourteen students, 

 who, without an exception, correctly noted changes of direc- 

 tion, go to show that the hearing is affected by phase varia- 

 tion in the waves reaching the ears. Examining the data 

 more carefully, we can divide them into two parts. Up to a 



