286 GENERAL SCIENCE 



Children after starting to school often weaken their eyes 

 by studying where the lights are too dim or too bright, 

 or by sitting so that the light can shine into the eyes, or by 

 reading books containing too fine print. 



A book or paper should be held from ten to fifteen inches 

 from the eyes for average sized print. While reading, the 

 head should be held almost erect and the light so placed 

 that it does not shine into the eyes; if possible the light 

 should come over the left shoulder. Trying to read in 

 dim light and leaning the head forward while reading 

 cause pressure on the eyeballs, and nearsightedness may 

 result. The eyes need rest the same as any other part 

 of the body. If the eyes pain after long-continued work, 

 the muscles controlling their adjustment need rest. Do 

 most reading, writing, and sewing in daylight, especially 

 if your eyes are slightly weak. Use shades on lamps, be- 

 cause most lamps throw most of their light upward and 

 cast a shadow at their base. This shadow often falls on 

 the book being read if a shade is not used to reflect the 

 light downward. If properly used, the shade will also 

 keep the light from shining directly into the eyes. In- 

 flamed or weak eyes are often aided by bathing with a 

 cupful of lukewarm water in which a teaspoonful of boracic 

 acid has been dissolved. 



196. Light and Health. Sunlight is essential to the 

 growth of trees, vegetables, and the cereal grains. These 

 plants have a pale green, sickly look when for several 

 days they do not get the proper amount of light. The 

 heat and light of the sun furnish directly the energy for 

 the growth of plants upon which man is dependent for 

 food, clothing, and shelter. Artificial light is not sufficient 

 for the growth of vegetation. 



Man, like plants, without sunlight turns pale, has a 



