6 THE POPULAR SCIENCE MONTHLY. 



complementary hue. As black is really a dark gray, we should expect 

 to find it also assuming, to some extent, a color complementary to that 

 of the ground, and this is indeed the case, though the effect is not quite 

 so marked as with a gray of medium depth. Chevreul, in his great 

 work on the simultaneous contrast of colors, relates an anecdote which 

 illustrates the matter now under consideration : Plain red, violet-blue, 

 and blue woven stuffs were given by certain dealers to manufacturers, 

 with the request that they should ornament them with black patterns. 

 When the goods were returned the dealers complained that the pat- 

 terns were not black, maintaining that those traced on the red stuffs 

 were green ; on the violet, dark greenish-yellow ; and on the blue, cop- 

 per-colored. Chevreul covered the grounds with white papers in such 

 a manner as to expose only the patterns, when it was found that their 

 color was truly black, the effects which had been observed being entire- 

 ly due to contrast. The remedy in such cases is not to employ pure 

 black, but to give it a tint like that of the colored ground, taking care 

 to make it just strong enough to balance the hue generated by contrast. 

 If we substitute a white pattern for the black, something of this same 

 effect can often be observed, but it is less marked than with gray or 

 black. In cases like those now under consideration, the contrast is 

 stronger when the colored surface is bright and intense or saturated in 

 hue. The effect is also increased by entirely surrounding the second 

 color with the first ; the circumscribing color ought also to be consider- 

 ably larger than its companion. When these conditions are observed, 

 the effect of contrast is generally noticeable only on the smaller sur- 



UlARX^IMUliE 



CYM BLUE 



ULTRAMARINE 



CYAN BLUE 



Fig. 9.— Akkangeseent to show the ErrECTS of Simultaneoub Contrast (ONE-HAxr Size). 



face, the larger one being scarcely affected. When, on the other hand, 

 the two colored surfaces are about equal in extent, then both suffer 

 change. If it is desired to produce a strong effect of contrast, the col- 

 ored surfaces must be placed as near each other as possible. This is 

 beautifully illustrated in one of the methods employed by Chevreul in 

 studying the laws of contrast. Two colored strips were placed side by 



