HEARING 421 



existence of several thousands of resonators tuned to as many 

 notes of different pitch. It remains for the physicists to say 

 whether or not we may picture one of these minute resonators 

 as responding to a given note in 10 separate octaves, another in 

 9 ... another in only 1. The physicists, on their part, may 

 very properly ask the anatomists to point out the resonators, 

 and even to reproduce them in models of dimensions which 

 allow of experimental investigation. 



It is generally agreed that the sensation of a chord is com- 

 pounded of the sensations to which each of its constituent 

 tones gives rise, and that our power of analysing the com- 

 pound is a question of attention. A musician can direct his 

 attention to either sensation at will. It is not equally certain 

 that a person who has no knowledge of music can do the same. 

 Familiarity with musical instruments gives us so exact a know- 

 ledge of the way in which compound tones are produced that 

 it becomes a difficult matter to decide whether, when we say 

 that we can pick out the E or the G of the common chord, it 

 means that we can hear it as distinct from C and C', or whether 

 it means that, knowing the constitution of the chord, we think 

 about the E or the G when we hear the compound tone, to 

 the exclusion of its other constituents. Then, again, the 

 several strings which we try to strike simultaneously do not 

 actually " toe the line." Their vibrations are not in the same 

 phase, even though the strings be in absolute tune. Dis- 

 crepancy of phase may favour the singling out of the several 

 constituents of the chord. There we touch upon a problem 

 which we passed over in silence when attempting to give an 

 idea of the nature of the pulsations which reach the ear. We 

 then (p. 405) described the partial pulsations which are super- 

 imposed upon the main pulsation as if they necessarily started 

 simultaneously with it. We assumed that the phase difference 

 of the partials was zero. But it is clear that differences of 

 phase of its constituent tones may produce an almost infinite 

 number of variations in the form of a compound " wave " of 

 sound. Is the ear variously affected by different forms of 

 wave ? Does difference of phase result in difference of sensa- 

 tion ? In broad terms, the answer to this question must be 

 in the negative ; although it can be shown that in certain cases 

 a change in phase of the several constituents of a compound 



