204 



NATURE 



{June 29, ii 



holtz's time, the theory had been propounded that quality abandon the new hypothesis that the ear thus decomposes 

 depended on the form of the vibrations of the wave of complex tones into simple ones, or else to establish by 

 sound ; but since differences of phase greatly affect the experiment that no difference of phase affected the [per- 

 form of the vibration, Helmholtz was forced either to ception of quality by the ear. 



Fig. i. — Resultant curves formed by compound 



of equal intensity but differing in phase. 



The difference of form introduced into a complex forms of a note and its first eight upper partials, each of 

 vibration by a difference of phase between its components the nine tones being of equal intensity. Of the four 

 is already known ; but Kcenig has brought forward some curves ranged in line the first corresponds to the result- 

 very striking examples. Fig. la, for example, gives the ant when the components start at similar phases, each 

 curves which result from compounding together the wave- component beginning from zero with descending ordi- 



F G. 2.— Resul 



of pha 



nates. In the second of the row, each of the separate wave-length, and in the fourth case three-quarters of a 



component waves begins with a negative ordinate of wavelength. It will be noticed how very different these 



maximum amplitude, or differing in phase by one quarter curves are to the eve, though compounded of the same 



irom the first case. In the thud the difference is half a elements. It will also be observed that tbe curves for 



