HERMANN VON HELMHOLTZ 



tors may thus be put slightly out of tune, their 

 resonance is weakened, and thus the phase is altered. 

 Helmholtz stated the result as follows : ' Differences 

 in musical quality depend solely on the presence and 

 strength of partial tones, and in no respect on the 

 difference in phase under which these partial tones 

 enter into composition.' This statement has been dis- 

 puted by Lord Kelvin, on theoretical grounds, and by 

 Rudolf Konig, who has submitted it to the test of 

 experiment ; but Lord Rayleigh remarks, regarding 

 Konig's experiment, * the results are in harmony with 

 the view that would ascribe the departure from Ohm's 

 law, involved in any recognition of phase relations, to 

 secondary causes.' l Physically, timbre must be due to 

 the form of the vibration curve, otherwise telephoning 

 would be impossible ; but the ear always analyses the 

 curve into its constituents. 



With the view of establishing his theory of hearing 

 on a firm basis, Helmholtz made a careful examination 

 of the question of the existence of damping arrange- 

 ments in the ear. Suppose tones are pouring into the 

 ear in rapid succession, and that the effect of one tone 

 has not died away before the influence of the next one 

 is felt, musical effect would be disturbed. This would 

 certainly occur if we executed a shake on a piano of 

 eight or ten notes in a second, so that each note would 

 be sounded four or five times. But it is well known 

 that the sensation excited by such shakes is rough and 



1 Rayleigh, of. cit., vol. ii., p. 469. 

 ISO 



