CHAPTER VII 

 THE WOKK OP SUNNING WATER 



The Sphere of Activity of Rain. When rain falls upon 

 the ground, it may do one of three things. It may evapo- 

 rate immediately from the surface and return to the air ; 

 or it may run rapidly off the surface and quickly join 

 the streams and rivers which bear it to its final goal, the 

 sea; or it may sink into the ground. In this last case 

 part of it returns gradually through capillary action to 

 the surface, where it is again evaporated; part finds its 

 way into springs; and part sinks deep into the soil and 

 rock. 



Experiment 74. (Teacher's Experiment.) Attaclvone end of a 

 rubber tube to a faucet in a sink. In the other end of the rubber 



tube insert a glass tube 

 drawn out to a point, so 

 that when the faucet is 

 opened the water will issue 

 from the glass tube in a fine 

 FIGURE 79 stream. Arrange to play 



this stream into the concave 



surface of a spoon so that the reflected and widened spray will fall 

 over about a square foot of surface. (Figure 79.) 



Take a long, shallow, flat-bottomed pan and punch a row of holes 

 in one end of it, a little above the bottom. At the other end, and 

 covering about two thirds of the bottom of the dish, arrange several 

 thin, irregular layers of fine sand, salt, fine clay, coal dust, or 

 other fine materials. Tilt the pan slightly so that the fine materials 



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