HERMANN VON HELMHOLTZ 



Helmholtz had forks constructed, the frequencies of 

 which were in the order of a harmonic series, beginning 

 with one having a pitch of 256 vibrations per second. 

 These were then Ut 2 (c), Ut 3 (<:'), Sol 3 (/), Ut 4 (c"\ 

 Mi 4 (O, Sol 4 (/'), l(b"\> nearly), Ut 6 (<"'), etc. They 

 were mounted on resonance boxes, by which the vol- 

 ume of sound was much augmented. Thus any 

 combination of the partials with the prime could 

 be readily obtained by suitable bowing, and at the 

 same time while the compound tone fell on the ear, 

 the observer could effect an analysis by means of 

 resonators. Since the invention of this method, 

 Rudolf Konig has adapted his beautiful device of 

 manometric flames, aided by the rotating mirror of 

 Wheatstone, for the demonstration of the analysis of 

 a compound tone. 1 



It will be evident that various combinations of the 

 waves of the prime with those of the partials will 

 produce varieties of wave form, and that the form of 

 the resultant wave will be modified by the phase and 

 the amplitude of the constituent waves. But we have 

 seen that the ear can resolve musical tones into a 

 series of partials, and that it behaves in accordance 

 with the proposition advanced by Ohm, namely, that 

 the human ear perceives pendular vibrations alone as 

 simple tones, and resolves all other periodic motions of 

 the air into a series of pendular vibrations, hearing 



1 For a figure of the apparatus, see M'Kendrick's Physiology, vol ii., 

 p. 686. 



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