14 



A. M. Mayer — Researches in Acoustics. 



fork is kept in action and the disk revolved with the same 

 velocity ; then another three seconds period of sound is given 

 the ear. This is best done by placing the rubber tube in the 

 meatus of the ear and pinching the end of the tube between 

 the fingers. By relieving the pressure more or less we can 

 regulate the intensity of the sound which enters the ear, or we 

 can shut the sound off. The other ear is tightly closed with 

 beeswax softened with a little turpentine. 



Within the limits of the intensities of sound used in these 

 experiments I found no change in the duration of the sensa- 

 tion with change in the intensity of the sound. It seems 

 probable that such connected changes exist. If they do exist, 

 then it would appear, from the smoothness of the curve I 

 have obtained from the experiments, that the relative mean 

 intensities of the sounds used did not vary sufficiently to make 

 apparent any change in the duration of the after-sensation with 

 change in the intensity of the stimulus. 



Table of results of experiments. The empirical formula which 

 gives the relation of the pitch of a sound to the duration of its 

 residual sonorous sensation. 



The results of the experiments made with the various forms 

 of apparatus just described are given in the following Table I. 













Table I. 











A 



B 



c 



D 



E 



F 



G 



H 



I 



K 



L 



UTi 



64 



23-1 



1 



•0361 



•0369 



— •0008 









1-38 



UT 2 



128 



36 



1 

 ~i 3-2 



•0231 



•0228 



— •0003 



0280 



0324 



+ -0044 



1-77 



SOL„ 



192 













•0232 



•0237 



+ •0005 





UT 3 



256 



62 



1 

 "7T - 4 



•0134 



•0133 



—•0001 



•0190 



•0189 



-0001 



2-06 



Mi 3 



320 



73 



1 



"ST* 5 



•0114 



•0112 



-•0002 



•0160 



•0158 



-•0002 



2-12 



SOL 3 



384 



88 



1 



1 5"' 6 



•0094 



•0097 



+ •0003 



•0137 



•0137 



•0000 



2-18 



UT 4 



512 



108 



1 



13 



•0077 



•0078 



+ •0001 



•0110 



•0109 



-•0001 



237 



Mi 4 



640 



126 



_i_ 



•0066 



•0067 



+ •0001 



■0092 



•0092 



•0000 



2 53 



SOL 4 



768 



143 



1 

 17 1*6 



•0058 



•0059 



+ •0001 



•0080 



•0081 



+ •0001 



2 68 



UT 6 



1024 



170 



1 

 2 04 



•0049 



•0049 



—•0000 



•0066 



•0066 



•0000 



301 



Mi 5 



1280 













•0057 



•0057 



•0000 





SOL 5 



1536 













•0052 



•0052 



•0000 





Ute 



2048 













•0045 



•0044 



-•0001 





Mi 6 



2560 













•0039 



•0039 



•0000 





SOL 6 



3072 













•0036 



•0036 



•0000 





Column A. gives the names of the sounds, and B the num- 

 bers of their vibrations (v. d.) per second. C, the number of 

 beats of interrupted sound received by the ear in a second to 

 blend into a continuous uniform sensation. In column D are 

 the durations of the residual sonorous sensations expressed in 

 vulgar fractions. The numbers in column D are obtained, as 

 already explained, by diminishing the reciprocals of the num- 

 bers in col. C by ^. Under E are the fractions in column D 



