466 THE POPULAR SCIENCE MONTHLY. 



imperfect focusing. To understand this, let us for a second time 

 observe the artist before his easel. If he is painting a bunch of 

 flowers, with a white rose near the center, and if he wishes this 

 rose to stand out in strong relief, he focuses his eyes naturally 

 and normally upon it, and reproduces on the canvas the same 

 clearly denned, well-focused flower which he sees. To the other 

 flowers of the cluster he does not care to give the same promi- 

 nence, and sketches them with less distinctness, or else focuses 

 his eyes purposely for a point in front of the bouquet or behind 

 it, thus blurring the colored flowers and purposely transferring to 

 the canvas an ill-defined image of them. For example, teachers 

 often find fault with their pupils, saying, " The trouble is, you see 

 too much ; you should not paint so exactly." An artist, holding 

 an important public position as a teacher of painting in Boston, 

 recently showed me lenses which were .used by the students when 

 learning thus to focus the objects imperfectly. Given, then, this 

 fact of imperfect vision on the part of the artist, either in the 

 form of astigmatism or in the form of undue contraction of the 

 focusing muscle, let us consider its effect in relation to three 

 factors namely, drawing, values, and color. 



As to the first, imperfect vision is unquestionably a disadvan- 

 tage, as we have seen. The draughtsman owes his power to two 

 things accuracy of eye, which enables him clearly to perceive 

 forms ; and dexterity of hand, which enables him to reproduce 

 them. Truth in one is as indispensable as in the other. 



Next, as to the question of values. This term, as we know, is 

 used in a certain sense to express perspective, or, more exactly, 

 the relative distance of an object in the foreground as compared 

 with another more or less in the background. In the case of the 

 bouquet, just cited, the white flower in the center, having the 

 highest relative value, is painted exactly in focus. A certain 

 amount of artificial adjustment of focus by the artist is an un- 

 doubted advantage for the rest of the bouquet, however, and the 

 habit of focusing the eye for some point in front of the picture 

 or beyond it is, therefore, practically universal among artists, 

 though in most instances they are not conscious of the act. In a 

 similar way the effects called technically " distance " and " at- 

 mosphere " are also best secured in this way. The two factors 

 thus far considered relate to representations in black and white 

 as well as to those in color. 



We come now to consider the third factor, that of the mix- 

 ing of colors. We shall find that this involves the blurring 

 or overlapping of images on the retina, which can be caused 

 by astigmatism, if it exists in sufficient degree, or by improper 

 focusing. It is usually produced by both of these together 

 and by another function dependent on the combination and 



