3 2 



ELEMENTARY SCIENCE 



deeper it goes the smaller are the cracks and pores. At 

 last the pressure is so great that all cracks and pores are 

 closed up. Probably there is no water deeper than a 

 few miles in the earth. 



When wells are dug water is sometimes found quite 

 near the surface, sometimes far below it. The level at 

 which water begins to collect in the well is called the ground- 



FIG. 10. Diagram showing how the ground-water level (indicated by the dotted 

 line) follows the curves of the land. 



water level, or the water-table. The water-table is the top 

 of the water that is under the ground. The top of the 

 water that is in lakes or streams is level, but the top of 

 the water that is in the ground is not level. It follows the 

 curves of the land, and rises higher than the tops of streams 

 and lakes. This you can understand better by studying 

 the picture (see Fig. 10). Between rains, the water-table 

 sinks, for the ground-water keeps seeping out into wells 

 and springs, into lakes and rivers. 



Under the ground the water does not flow evenly in 

 all directions. This is because there are so many differ- 

 ent kinds of rock and soil. The different kinds of rock 

 and soil are found usually in layers. These layers are 



