92 ON THE PHYSIOLOGICAL CAUSES OF 



the physiological constitution of the ear which we have just 

 considered, becomes clear by comparing it with that of the eye. 

 Light is also an undulation of a peculiar medium, the lumi- 

 nous ether, diffused through the universe, and light, as well 

 as sound, exhibits phenomena of interference. Light, too, has 

 waves of various periodic times of vibration, which produce 

 in the eye the sensation of colour, red having the greatest 

 periodic time, then orange, yellow, green, blue, violet; the 

 periodic time of violet being about half that of the outermost 

 red. But the eye is unable to decompose compound systems of 

 luminous waves, that is, to distinguish compound colours from 

 one another. It experiences from them a single, unanalysable, 

 simple sensation, that of a mixed colour. It is indifferent to 

 the eye whether this mixed colour results from a union of 

 fundamental colours with simple or with non-simple ratios of 

 periodic times. The eye has no sense of harmony in the same 

 meaning as the ear. There is no' music to the eye. 



^Esthetics endeavour to find the principle of artistic beauty 

 in its unconscious conformity to law. To-day I have endea- 

 voured to lay bare the hidden law, on which depends the 

 -agreeableness of consonant combinations. It is in the truest 

 ;sense of the word unconsciously obeyed, so far as it depends on 

 the upper partial tones, which, though felt by the nerves, are 

 not usually consciously present to the mind. Their com- 

 patibility or incompatibility, however, is felt without the hearer 

 knowing the cause of the feeling he experiences. 



These phenomena of agreeableness of tone, as determined 

 solely by the senses, are of course merely the first step towards 

 the beautiful in music. For the attainment of that higher 

 beauty which appeals to the intellect, harmony and dysharmony 

 -are only means, although essential and powerful means. In 

 dysharmony the auditory nerve feels hurt by the beats of incom- 

 patible tones. It longs for the pure efflux of the tones into 

 harmony. It hastens towards that harmony for satisfaction and 

 rest. Thus both harmony and dysharmony alternately urge 

 -and moderate the flow of tones, while the mind sees in their 

 immaterial motion an image of its own perpetually streaming 



