CARE OF THE EYES. 313 



do not face a window, another light, a mirror, or white wall, 

 if it can be avoided. In a room, white walls are likely to 

 injure the eyes. Choose a dark color for a covering for a 

 reading-table. Sewing against the background of a white 

 apron has worked serious mischief. Direct sunshine very 

 near the book or table is likely to do harm. 



2. Preferably have the light from behind and above. Many 

 authors say "from the left," or "over the left shoulder." 

 In writing with the usual slant of the letters this may be 

 desirable. But vertical writing is now strongly advocated, 

 as it enables one to sit erect, and have the light from above 

 and equally to the two eyes. Having stronger light for one 

 eye than for the other is bad. Sitting under and a little 

 forward of a hanging lamp will thus give the light equally 

 to the two eyes and send no light direct into the face. In 

 reading by daylight avoid cross-lights so far as possible. 

 The incandescent electric light has an advantage in being 

 readily lighted, without matches, and in giving out little heat, 

 thus making it valuable for house-lighting ; but owing to its 

 irregular illumination (due to the shadow cast by the wire 

 or filament), it is not well suited for study or other near work. 

 For this purpose an Argand gas or kerosene burner is much 

 to be preferred, since it throws a soft, uniform, and agreeable 

 light upon the work. 



3. Reading out-of-doors is likely to injure the eyes, es- 

 pecially when lying down. To try to .read while lying in a 

 hammock is bad in many ways. Too much light directly en- 

 ters the eye, and often too little falls upon the printed page. 



4. Do not hold the book or work nearer the eyes than is 

 necessary. So far as possible avoid continuous reading in large 

 or heavy books by artificial light. Such books being hard 

 to hold, the elbows gradually settle down against the sides 

 of the body, and thus, without thinking about it, the book 



