and on Reed Organ-Pipes. 235 



tributed them among the different properties of the aerial pulsa- 

 tions as follows. The pitch depends on the number of vibrations 

 in a given time. Loudness on the greater or less extent of the 

 excursion of the particles. Quality and the vowel sounds, he 

 thinks must depend on the form of the curve by which the law 

 of density, and velocity in the pulse is defined, or upon the lati- 

 tude of the pulse, but this he offers as a mere opinion, unsup- 

 ported by experiment, save that* to account for the peculiar 

 property of sound, by which we know a flute from a trumpet, &c. 

 he remarks, that as the vibrations of each instrument are excited 

 in a manner peculiar to itself, its pulsations must also follow 

 peculiar laws of condensation and motion, by which he thinks 

 the sound will be characterized. 



It is agreed on all hands, that the construction of the organs 

 of speech so far resemble a reed organ-pipe, that the sound is 

 generated by a vibratory apparatus in the larynx, answering to 

 the reed, by which the pitch or number of vibrations in a given 

 time is determined ; and that this sound is afterwards modified 

 and altered in its quality, by the cavities of the mouth and nose, 

 which answer to the pipe that organ builders attach to the feed 

 for a similar purpose. Accordingly, the whole of the phenomena 

 I am about to describe, will be found to result from the appli- 

 cation of reeds to pipes and cavities of different and varying 

 magnitude. 



Now it is important to the success of these experiments, that 

 the tone produced by the reed should be as smooth and pure as 

 possible. The coarse tone of the common organ reed completely 

 unfits it for the purpose, and hence we find both Kempeien and 

 Kratzenstein endeavouring to ameliorate it. Kempeien made the 

 tongue of ivory, and covered its under side as well as the por- 



• Schol. II. Prob. 80. 

 GG2 



