470 THE POPULAR SCIENCE MONTHLY. 



habit of making lid-pressure on the cornea, the resulting astigma- 

 tism being of no advantage, but always a disadvantage. 



2. If he wishes to render himself relatively near-sighted, or, as 

 he would state it, throw the eye out of focus, it is better to wear 

 at his work a pair of convex glasses. The inconvenience of re- 

 moving and replacing these could be obviated by spectacles made 

 after the plan of the ordinary bifocal glasses, or, still better, by 

 having the upper half cut away entirely, leaving for the lower a 

 convex glass of such a strength as that individual would find 

 most convenient for his special variety of work. In this way he 

 is at least rid of the annoyance of constantly walking back and 

 forward to obtain the effect of distance. 



3. It is an undoubted advantage to every artist to ascertain 

 the degree in which his eyes vary from the normal standard. 

 Such a formula could be easily obtained. If the degree of error 

 is but slight, of course it can be disregarded ; if decided, and not 

 properly corrected, knowledge of that variation from the normal 

 in the artist's vision, if given in some way to the observer, would, 

 without doubt, often win more favorable criticism for his work. 



The logical and imaginative reader will perhaps picture to 

 himself the art catalogue of the future, with a formula for the 

 amount of imperfect vision (ametropia, as the oculists call it) 

 added to each title. Thus : 



No. 42. A Summer Morning. Myopic astigmatism, 1'5 dioptre, 

 vertical meridian. 



No. 44. He Cometh Not. Cylindrical, minus 0'5 dioptre, with 

 spherical, minus 1"5, axis forty-five degrees. 



This may seem rather like the " schedule of emotions," as it was 

 once called, which was printed on the weekly programme in the 

 earlier days of the Boston Symphony Orchestra, . but none the 

 less some such cataloguing of pictures would probably assist the 

 critics and give the artist the satisfaction of more praise. 



4. As the .corollary of the last proposition it should be said 

 that the observer, in order to see a picture to the best advantage, 

 must adjust his vision to that of the artist who produced it. Most 

 of us do this instinctively. Not only do we select the best point 

 of view from which to observe a picture, but we recede from the 

 painting until the lights and colors blend in just the right degree. 

 In addition to that, many instinctively pinch the eyes together, 

 producing thus a momentary astigmatism, such as the artist had 

 produced in his own eye, and find the picture thus apparently 

 improved. A most useful appliance for viewing pictures is the 

 so-called stenopaic slit. This is merely a slit one or two millime- 

 tres in width in a card or thin plate of brass. Simple as this de- 

 vice is, but few persons are aware of how much it adds to the 

 effect in viewing paintings, as it allows the rays of light in only 



