Sounding of two Notes. 427 



same way the upper beats at about 18 begin to be distinguish- 

 able by the roughness of the clang. 



In the third period, from d \g" to d :d /f , about 16 beats 

 m can be heard, and about 10 beats m! . 



(I made these two observations upon my tonometer with 

 tuning-forks which are not mentioned in the list given in my 

 introduction.) 



Below and above the interval d : d" (1:5) about 5 beats 

 are easily heard, and in the interrupted interval V \g"' (1 : 6) 

 from 2 to 3 can be distinguished. 



The beat-notes, which in the first period were already ex- 

 tremely feeble, in the higher one are no longer directly per- 

 ceptible. 



D. Intervals with the fundamental note c"(=1024 v. s.). 



In intervals with the fundamental note c f/ , the lower and 

 upper beats are only to be distinguished as such near the unison 

 and the harmonic interval. In consequence of their great 

 numbers they change to notes which in the different intervals 

 will be heard in the following manner : — 



In the second, c" d /f , the note m (64 beats) C is distinctly 

 heard ; in the third, c" d' ', it has risen to c (128 beats), and 

 is still distinct ; in the fourth the note m (170*6 beats) / is 

 joined by the note m" (341*3 beats) f. These two notes 

 blend, when the fourth is quite pure, into a clang that is heard 

 sometimes as f and sometimes as f. The notes m and m! 

 become equal at the fifth c" g f/ , when d is very distinctly 

 heard. At the sixth, the lower note m rises to f f y and the 

 note m' sinks to /. These two notes are more powerful, and do 

 not blend into one another so closely as at the fourth. If, 

 with exactly the same intensity of the fundamental note the 

 fork a" is held a little further from the ear, the / is heard more 

 strongly ; if it is brought nearer, f becomes more distinct. In 

 the interval c ff : 1792 v. s. (4 : 7) the two notes m=g / and 

 m=d are heard almost equally loud. At the seventh no more 

 is distinguished of the lower note, and mf = 64 beats forms a 

 mere rattle, a roughness through which C cannot be heard. 

 Above the octave, in the interval c" \d'" (4: 9), the note 

 W2=128 beats, C, can be faintly heard, and in the interval 

 c": 2889*3 v.s. (3:7), the note /. At «":«"' (2:5), where 

 m=m / = 256 beats, d is very distinct ; beyond these limits no 

 more beats can be distinguished ; only below and above the 

 twelth e" \g'" some distinct, and at the double octave a few 

 very weak beats may be heard. 



