298 AVERS. [Vol. VI. 



two qualities already considered, and to them alone, acting upon 

 or conditioning numerous secondary vibrations which always 

 accompany musical sounds, especially those produced by ordi- 

 nary means. It is also true that the klangfarbe is due more to 

 education than to anything else, for to ordinary ears the finer 

 qualities of klangfarbe are unperceived. 



Consequently the tonal differentiation which has been pre- 

 viously referred to the klangfarbe as form of the acoustic wave 

 must be referred to the two primary and only modifying influ- 

 ences. Timbre is due to the sequential propagation of the same 

 (or nearly the same) accented series of sonorous undulations up 

 the cochlear hair band. The accent may occur either before or 

 after the arrival of the other member ; i.e. the recurrence of the 

 series may be marked by the accent or fundamental tone, or the 

 latter may occur in any part of the series, provided it recurs in 

 the same (or nearly the same) relative position with reference 

 to the other tones. 



Ordinarily these tones follow each other with a rapidity, when 

 their faintness is considered, which prevents their being recog- 

 nized as separate tones, but this is by no means always the 

 case ; for some of the partial and harmonic tones accompanying 

 the fundamental note, e.g. of a piano string, are readily distin- 

 guishable as independent tones when attentioji is paid to them 

 alone. It is also true that other tones of the harmonic series 

 stand in the same relation to the main partials that these occupy 

 with reference to the fundamental. 



It should be borne in mind that the perception of sound by 

 the ear does not follow with mathematical accuracy the laws of 

 physical acoustics. 



The rhythm of intensities is, then, the cause of the timbre of 

 tones. We may illustrate in a crude way how the same nerve 

 fibres may send sequential stimuli of different intensities, and 

 give rise by increase of rate into blended sensations. 



Suppose we fill a sufficiently long glass tube of small calibre 

 with liquids of sweet, sour, bitter taste in the order given, each 

 taste occupying a few millimetres' length of the tube and strong 

 enough to give rise to the special sensation, yet weak, evanescent 

 enough not to fatigue the nerve or persist in the tongue to the 

 detriment of the experiment. Starting slowly, cause the liquid 

 to flow in a stream over the tongue, and there will follow sue- 



