468 THE POPULAR SCIENCE MONTHLY. 



of the spectrum produces white, as was first shown by Helmholtz, 

 but when these pigments are mixed they produce green. Such 

 examples might be multiplied to a considerable extent. The rea- 

 son why the mixture of colors in the spectrum differs in the re- 

 sults from the mixture of pigments is due to the fact that the 

 pigments are not pure colors. Every red contains some blue or 

 yellow, the yellows contain some blue or red, and the blues con- 

 tain some red or yellow. Not only does the actual mixture of 

 pigments produce effects differing from those caused by the mix- 

 ture of the same colors in the eye, but the mere juxtaposition of 

 the two pigments on the canvas influences the color of each, even 

 when they are both properly focused in the eye. Thus, if small 

 spots of pure yellow and blue are placed side by side, we see that 

 the yellow inclines to red and the blue to violet. But if the 

 spots are blurred and blended by making the eye sufficiently 

 astigmatic by improper focusing, then by this or other optical 

 combination it is possible to obtain shades of gray. In a word, 

 the combination is in a " higher key." These and similar facts 

 have been gradually worked out on the one hand in the labora- 

 tory by the physicists, and on the other by those who were 

 constantly experimenting with pigments as they were mixed 

 on the palette. Only a few painters know the scientific prin- 

 ciples involved, but many had stumbled upon the practical re- 

 sults, and of late a new and almost distinctive class has arisen, 

 whose usual practice it is not to mix the colors on the palette, 

 but, consciously or unconsciously, to so arrange them on the 

 canvas that they blend in the eye when properly viewed. This 

 is one of the distinctive features of the so-called school of impres- 

 sionists. It is easy to see that unusual care and fine artistic sense 

 must be exercised in attempting any such trick with pigments. 

 A genius may succeed at this, but the result for a mere imitator 

 is disastrous. The effect is that produced when a certain artist by 

 chance sat down on his freshly prepared palette. " Ah ! " said his 

 friend, " that is the best picture you ever produced. Cut it out, 

 call it ' An Old-time Garden/ and it will sell for a fortune." In 

 spite of the ridicule which this class of painters has brought upon 

 itself, it must be said in justification that the method has a certain 

 basis of scientific truth, and that good effects, striking effects, if 

 not the best effects, can often be obtained by this mixture of col- 

 ors, not on the palette, but in the eye. But this method of arrang- 

 ing colors demands as its correlative a certain amount of imper- 

 fect vision. In order to see such pictures at their best, it is neces- 

 sary to view them from a considerable distance, as we have seen 

 the artist do in his studio, or else, approaching the picture, pinch 

 the cornea by means of the lids into a marked degree of astigma- 

 tism, or, consciously or unconsciously, contract the ciliary muscle 



