600 NATURE STUDY. 



Compare the throwing out of water by the leaves (trans- 

 piration, the botanists call it) with the throwing out of 

 water by the skin, or perspiration. Perhaps the children 

 can discover, in old leaves, that the leaf, too, has a skin. 



LESSON X. HOW THE LEAVES AND THE SUN WORK 

 TOGETHER. 



Study the leaves in relation to the light. Note how all 

 the leaves of the bean turn toward the light. Turn the 

 box around so that leaves face away from the light. How 

 soon they twist around. 



Any plants growing away from the window show how 

 the leaves grow toward the light, often greatly lengthening 

 their stems to get nearer the light. 



Bean plants, whose leaves are shaded by other plants, or 

 bean plants put in a dark place, soon lose their bright green 

 color and look sickly. 



Plants grown in a sunny window are much greener and 

 much more thrifty looking than those which do not get 

 the sun. 



Evidently our bean leaves love the sun. Why ? Does 

 the sun help them ? Show the children plants which have 

 been in the cellar all winter. Ask them to turn over 

 boards and stones, and see the color of the leaves under 

 them which are hidden from the sun. How yellow or pale 

 they look ! 



The sun helps the leaves by giving them their green 

 color, and by keeping them healthy. A review of the ex- 

 periments in the previous lesson, putting all emphasis on 

 the difference, in the throwing out of water, between plants 

 in the sun and those in the shade, will show even the little 

 folks that the sun also helps the leaves throw out water 

 somewhat as it helps the water in lake and river and on 

 street and walk to pass into the air or evaporate. 



