§55 VII. SIMULTANEOUS CONTRAST. ' 103 



are to be generally viewed. Some colours again are suited to 

 great heights ; others to positions nearer to the ground ; and 

 to introduce dark reds, browns, and heavy colours on the 

 upper parts of a room, and bright yellows, blues, or any very 

 light tones close to the floor, would have as disagreeable and 

 inconsistent an effect as to place the lightest ornamental work 

 on the lower portion of a building and the most massive on 

 the upper part. 



M. Chevreul has very properly insisted on the " simulta- 

 neous contrast of colours," and " of tones of colour," and the 

 diminution or the increase of intensity of each when in con- 

 tact, according to their relative qualities, in which he is per- 

 fectly justified by experience. Among other examples he cites 

 the colours of the rainbow, which " are modified by their jux- 

 taposition, inasmuch as isolated they appear of different hues 

 than we see them ; " and though the subject of " simultaneous 

 contrast of colour " was known and studied long ago, he has 

 added greatly to previous observations by many valuable ex- 

 periments, for which we are the more indebted to him, as they 

 correct some erroneous conclusions, and substitute practice for 

 theory; and his remarks on the effects of colours upon each other 

 when seen together are just and worthy of attention (p. 34). 

 What he says of " successive contrast " is also important ; and 

 though it should be attended to by persons who examine 

 fabrics of the same hue, or copy a particular colour for a long 

 time, it has not the same bearing on a pattern of many 

 colours; and this may also be said of his "mixed contrast;" 

 in relation to which he gives some curious facts, (pp. 35-38.) 



It is true if the eye looks for a long time at a red colour 

 that the accidental or " complementary " green image of it 

 does sometimes take its place on the retina ; but this is only 

 when the eye has become so fatigued by looking at it as 

 to lose its previous power of seeing the true colour. There 

 are also certain moments when the retina is more readily 



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