1873 •] Colours and their Relations. 101 



the normal ear of a simple musical note. In colour there 

 is always involved the idea of superficies ; and although 

 time is also really involved, yet the rapidity of vibration is 

 such that the mind can form no conception of it whatever. 

 In music, on the other hand, there is not involved any idea 

 of superficies; whereas time is an indispensable element in 

 the conception of a musical note. Again, there is in music 

 nothing corresponding to complementary colours or to the 

 perception of mere whiteness, which can be produced by a 

 combination of such. 



Harmony in music is produced by the simultaneous im- 

 pulse on the ear of two or more combined sounds, whose 

 rates of vibration stand to each other in certain definite 

 arithmetical relations; and whenever there is any departure 

 from those relations the result is either dissonance or dis- 

 cord. When two or more colours fall simultaneously on the 

 same point of the retina, the result is a compound colour, 

 which may or may not be pleasing to the eye ; but the mixture 

 of adjacent colours in the spectrum is not displeasing to the 

 eye, as would be the simultaneous sounding of two adjacent 

 musical notes to the ear. What is called harmony in colour 

 depends, not on the simultaneous impulse of two or more 

 waves of colour on one and the same point of the retina, 

 but on the juxtaposition of two or more colours without 

 admixture. The effect seems to depend on the definite 

 arithmetical relations which the rates of vibration corres- 

 ponding to the colours bear to each other, as in the case of 

 sound. 



These effects of the juxtaposition of colours, however, are 

 much more analogous to melody in music than to harmony. 

 The pleasing impression, for example, produced by the 

 gradual blending of the adjacent colours in the refracted 

 spectrum is analogous to the slide in the violin. The juxta- 

 position of pure orange and pure violet doubtless owes its 

 agreeable impression to the circumstance that these two 

 colours stand to each other in the same ratio as do the do 

 and sol of the musical scale. In like manner the effect pro- 

 duced by the juxtaposition of pure red and pure green is 

 due to their standing to each other in the same ratio as do 

 and fa. So also with pure red and pure violet, which bear 

 the same mutual relation as do and la, or pure green and 

 pure violet, which are related as do and mi ; likewise pure 

 orange and pure green, which are related as do and mfo . 

 But in all these cases the effect is more analogous to that 

 produced by the striking of these notes in rapid succession 

 as parts of a melody, than to the harmony resulting from 



