ART AND EYESIGHT. 467 



contrasting of colors. All this is done unconsciously by the 

 observer. 



To make this point clear, a slight digression is necessary to 

 glance at the growth of painting. It must be remembered that 

 the earlier artists were religious enthusiasts. First, they painted 

 upon the walls of the basilicas and baptisteries ; but as the early 

 styles of architecture changed, and more and more of the wall 

 space was encroached upon by windows, canvas came into use, 

 and with opportunities thus increased painters grew more numer- 

 ous and more proficient. Their methods of procedure were as 

 simple as their faith, and there were but few efforts to produce 

 unusual effects. The pigments were mixed on the palette, and 

 thus mixed were transferred to the canvas. This was the method 

 until recent times, and by that method the great masterpieces 

 have been produced. 



It is true that the works of some of the great colorists before 

 which we bow down and worship to-day are not the pictures 

 painted by these artists. The pigments they used have faded, and 

 successive layers of varnish have changed them greatly. But in 

 all, whether well preserved, in a slightly pathological condition, 

 or in an advanced stage of decomposition, the point to be observed 

 is, that the pigments were mixed on the palette just as they were 

 placed on the canvas, and in looking at them no effort at accom- 

 modation of the eye or special focusing is required. If the eyes 

 of the observer are opened in a natural manner, he sees just what 

 was intended should be seen. In spite of certain variations from 

 this type, that was the condition of the art of painting until the 

 present generation. But, near the middle of this century a book 

 was published by Chevreul on the Principles of Harmony and 

 Contrasts of Colors, which by popularizing facts already known 

 undoubtedly exerted an important influence on the artistic mind, 

 especially in France. The principle to which I refer consists in 

 this, that the pigments mixed on the palette and transferred to 

 the canvas, as was the habit of earlier artists, do not produce 

 upon the human retina so marked or so true an effect as when the 

 proper pigments are placed unmixed but side by side on the can- 

 vas, and then viewed in such a blurred way that the rays from 

 each are superimposed upon the retina. It is not simply a theory 

 that the mixture of colors optically, produces effects quite differ- 

 ent from those obtained by the mixture of corresponding pig- 

 ments, but it is easily demonstrated. If we mix the rays of the 

 spectrum, as can be done by means of a lens or concave mirror, 

 the result is white light ; but if the very same pigments, as pure 

 as can be obtained, are mixed on the palette, we obtain not white, 

 but a dark gray indeed, in certain proportions we have almost a 

 black resulting. Again, the commingling of the yellow and blue 



