ON THE PSYCHO-PHYSICAL VIEW OF NATURE. 489 



entered into an analysis of the processes by which vocal 

 sounds and notes are produced, and showed their im- 

 portance in musical and linguistic theories. Combined 

 with all these deductions and applications, which started 

 from Fourier's mathematical analysis of compound move- 

 ments, Helmholtz's anatomical dissection of the organ of 

 hearing leads him to the conclusion that there " must 

 exist in the ear different parts which are set in vibration 

 by notes of different pitch, and which have thus a sensa- 

 tion of these notes." * And here he takes up a different 

 line of reasoning that suggested by Johannes Miiller's 

 theory of the specific sense energies. In his studies 

 in physiological optics he had already accepted Young's 

 hypothesis that there exist in the eye three distinct 

 kinds of nerve - fibres, to which belong distinct modes 

 of colour -sensation. Something analogous exists in the 

 ear. 2 " The differences in notes namely, pitch and ie. 



Analogy 



colour for character! are reduced to differences of the Between 



L J sound and 



sensitive nerve-fibres, and for each nerve-fibre there exists colour - 

 only the difference of the intensity of the stimulus." 



This brings the action of the sensory nerves into line 

 with that of motor nerves : everywhere the nerve itself is 



pitch, and, to the present day, Book of Physics,' Sound, p. 69) we 

 the English tongue has no equiv- ( read, " It is convenient to use the 

 alent for the French " timbre " or term note for an ordinary com- 



the German " Klangfarbe." Everett 

 used the word character, and so 

 does Lord Rayleigh. Dr Young, 

 in his "Essay on Music" (1800, 

 ' Miscell. Works,' vol. i. No. 5), 

 speaks of the quality of sound, 

 sometimes called its tone, register, 

 colour, or timbre (p. 118). In the 

 most recent scientific work on 

 sound in the English language 

 (Poynting and Thomson's ' Text- 



pound sound to which a definite 

 pitch may be assigned, and the 

 term tone for each simple harmonic 

 constituent which goes to form it." 

 There is an important note on the 

 terminology by Alex. T. Ellis, the 

 learned translator of Helmholtz's 

 'Sensations of Tone ' (1875, p. 36). 



1 ' Tonempfindungen,' p. 215. 



- Ibid., pp. 220, 221. 



