Dr. A. M. Mayer's Researches in Acoustics. 275 



This formula, however, only refers to my own auditory sen- 

 sation. It is a physiological law ; and I imagine that the 

 durations of these residual sonorous sensations will vary more 

 with different observers than do analogous visual sensations. 

 It is therefore to be wished that others will repeat these expe- 

 riments and obtain determinations which, when combined, will 

 give a law which may be accepted as the expression of the 

 average durations of the residual sonorous sensations. 



The results in column E are given graphically in the 

 curve I of fig. 11. The unit on the axis of abscissas is 

 100 v.d. The unit on the axis of ordinates is *01 second. 



The determination of the duration of the residual sensation 

 of UTi [64 v.d.] was very carefully made, and made many 

 times. The experiments gave '0361 second for the duration 

 of this sound. The formula gives '0369, which is ^ 5 greater 

 than the observed duration. The greatest difference existing 

 between the observed and computed duration of the remaining 

 sounds of the table is in the case of SOL 3 [384 v.d.], where 

 the computed is ^ greater than the observed duration. 



In column L of Table I. are given the number of wave- 

 lengths of the sounds which pass into the ear throuoh a hole 

 in the rotating disks when these interrupted sounds blend into 

 uniform sensations. The average number of wave-lengths 

 which pass a hole is about 2-J. As the sound rises in pitch, 

 more wave-lengths pass the hole ; thus, while only 1'38 wave- 

 length passes in the case of UT^ three wave-lengths pass in 

 the case of UT 5 . 



An examination of fig. 6 shows that sound passes to the 

 ear while a hole in the disk passes over three diameters of the 

 hole in the nipple of the resonator, while the distance between 

 the centres of neighbouring holes in the disk equals six 

 diameters of the hole in the resonator. Hence, to ascertain the 

 number of wave-lengths which enter the ear during the 

 passage of a hole in the disk across the hole in the resonator, 

 we must divide the number of vibrations per second of the 

 sound, given in column B ; by twice the corresponding 

 number in column C. 



2. On the Smallest Consonant Intervals among Simple 



Tones. ~~ 



When two simple tones which differ slightly in pitch are 

 sounded simultaneously, beats are produced, which become 

 more frequent as the difference in pitch increases, and with 



