76 ON THE RELATION OF OPTICS TO PAINTING. 



and methods of representation, forms a series of import- 

 ant and significant facts, which the physiologist, who 

 has here to learn from the artist, cannot afford to ne- 

 glect. The study of works of art will throw great light 

 on the question as to which elements and relations of 

 our visual impressions are most predominant in deter- 

 mining our conception of what is seen, and what others 

 are of less importance. As far as lies within his power, 

 the artist will seek to foster the former at the cost of 

 the latter. 



In this sense then a careful observation of the 

 works of the great masters will be serviceable, not only 

 to physiological optics, but also because the investigation 

 of the laws of the perceptions and of the observations 

 of the senses will promote the theory of art, that is, 

 the comprehension of its mode of action. 



We have not here to do with a discussion of the 

 ultimate objects and aims of art, but only with an ex- 

 amination of the action of the elementary means with 

 which it works. The knowledge of the latter must, 

 however, form an indispensable basis for the solution 

 of the deeper questions, if we are to understand the 

 problems which the artist has to solve, and the mode 

 in which he attempts to attain his object. 



I need scarcely lay stress on the fact, following as 

 it does from what I have already said, that it is not 

 my intention to furnish instructions according to which 



