430 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1951 



The scientific attitude with which the impressionists approached 

 their art is well known ; they themselves did not hesitate to acknowl- 

 edge their debt to science. Their spokesman, Pissarro, in answer to a 

 letter from de Bellio arguing that scientific research into the nature 

 of color and light, anatomy, and the laws of optics could not help the 

 artist, replied : 



Now everything depends on how this knowledge is to be used. But surely 

 it is clear that we could not pursue our studies of light with much assurance if 

 we did not have as a guide the discoveries of Chevreul and other scientists. I 

 would not have distinguished between local color and light if science had not 

 given us the hint ; the same holds true for complementary colors, etc. 



The neoimpressionists, Seurat and Signac, devoted themselves to 

 scientific research, studying Maxwell's experiments, Charles Henry's 

 treatises, the analj'ses of light and color made b}' the American scientist 

 N. O. Rood, and Chevreul's color theories. Until he severed his con- 

 nection with the neoimpressionists, Pissarro used to refer to this group 

 as the "scientific impressionists" as opposed to Monet, Renoir, and 

 Sisley whom he scornfully termed the "romantic impressionists." 

 Romantic or not, these painters were scientifically minded, too, for 

 Monet as well as Seurat had studied the optical discoveries of Helm- 

 holtz and Chevreul. Helmholtz, who was an exponent of Dalton's 

 atomic theory, pointed out in a work entitled "On the Relation of 

 Optics to Painting" a relationship between the atomic theory and the 

 appearance of certain effects of light. After stating that the turbid 

 appearance of the earth's atmosphere is caused by fine transparent 

 particles of varying density and refrangibility which fill the air, 

 Helmholtz says : 



But science can as yet give no explanation of the turbidity in the higher regions 

 of the atmosphere which produces the blue of the sky ; we do not know whether 

 it arises from suspended particles of foreign substances, or whether the mole- 

 cules of air themselves may not act as turbid particles in the luminous ether. 



It is hard to believe that this passage could have escaped the eyes 

 of a painter interested in Helmholtz's writings. Thus it is altogether 

 possible that a conscious interest in the effects of light and air joined 

 forces with a deeper and less conscious reaction to the startling facts of 

 the atomic structure of the universe to produce the impressionist 

 manner of painting. And indeed, when we examine the works of the 

 impressionists, we must admit that in fact they are less expressive 

 of light and air than they are of a world composed throughout of 

 dense, vibrating, and homogeneous particles of matter. 



At the end of the century painting began to move away from im- 

 pressionism and, in fact, away from the scientific spirit generally. 

 Gauguin, indeed, led a one-man crusade against the scientific attitude. 

 In a letter to Charles Morice dated April 1903, he says : 



