and on Reed Organ-Pipes. 'iA'J 



Si series of pulsations of this kind might be expected to produce 

 on our organs of hearing. 



If we examine the nature of our series, we shall find it 

 merely to consist of the repetition of one musical note in such 

 rapid succession as to produce another. It has been long esta- 

 blished, however, that any noise whatever, repeated in such rapid 

 succession at equidistant intervals, as to make its individual 

 impulses insensible, will produce a musical note. For instance, 

 let the musical note of the pipe be g", and that of the reed >c', 

 which is 512 beats in a second, then their combined effect is 

 g"...i^'...g"...g"...{bVi in a second) in such rapid equidistant suc- 

 cession as to produce c', g-" in this case producing the same effect 

 as any other noise, so that we might expect a priori, that one 

 idea suggested by this compound sound would be the musical 

 note c'. 



Experiment shows us that the series of effects produced are 

 characterized and distinguished from each other by that quality 

 we call the vowel, and it shews us more, it shews us not only 

 that the pitch of the sound produced is always that of the reed 

 or primary pulse, but that the vowel produced is always identical 

 for the same value of s. Thus, in the example just adduced, g" 

 is peculiar to the vowel A" (Tab. I.) : when this is repeated 512 

 times in a second, the pitch of the sound is c', and the vowel 

 is A": if by means of another reed applied to the same pipe it 

 were repeated 340 times in a second, the pitch would be /, but 

 the vowel still A°. Hence it would appear that the ear in losing 

 the consciousness of the pitch of s, is yet able to identify it by 

 this vowel quality. But this vowel quality may be detected to 

 a certain degree in simple musical sounds ; the high squeaking- 

 notes of the organ or violin, speak jilainly I, the deep bass 

 notes U, and in running rapidly backwards and forwards through 

 the intermediate notes, we seem to hear the series U, O, A, E, I, 



