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THE POPULAR SCIENCE MONTHLY 



for instance, have a normal refraction in its horizontal meridian, and be 

 short-sighted in its vertical meridian. Small differences of this kind 

 are found in almost every eye, but are not perceived. Higher degrees 

 of astigmatism, which decidedly disturb vision, are, however, not un- 

 common, and are, therefore, also found among painters. I have had 

 occasion to examine the eyes of several distinguished artists which 

 presented such an anomaly, and it interested me much to discover 

 what influence this defect had upon their works. The diversity de- 

 pends in part upon the degree and nature of the optical anomaly, but 

 its effect shows itself in different ways, according to the subjects the 

 artist paints. An example will explain this better. I know a land- 

 scape-painter and a portrait-painter who have both the same kind of 

 astigmatism ; that is, the refraction of the vertical meridian differs 

 from the refraction of the horizontal one. The consequence is, that 

 their sight is normal for vertical lines, but for hoi'izontal lines they are 



Fig. 2. 



Fia. 1. 



slightly short-sighted. Upon the landscape-painter this has hardly 

 any disturbing influence. In painting distant views, sharp outlines are 

 not requisite, but rather undefined and blending tones of color. His 

 eye is sufficiently normal to see these. I was struck, however, by the 

 fact that the foreground of his pictures, which generally represents 

 water with gently-moving waves,, was not painted with the same 

 truthfulness to Nature" as the middle and background. There I found 

 short horizontal strokes of the brush In different colors, which did not 

 seem to belong to the water. I therefore examined the picture with a 

 glass, which, when added to my eye, produced the same degree of 

 astigmatism as existed in the painter's eye, and the whole picture 

 appeared much more beautiful, the foreground being now as perfect as 

 the middle and background. In consequence of this artificially-pro- 

 duced astigmatism, I saw the horizontal strokes of the brush indistinctly, 



