WATER I 91 



springs and wells are formed 11m rater ili.n follows 

 mpenrious layer ii called frj b oi ground water, 

 to distinguish it from* the fifan moisture surrounding 

 each soil particle. It must not be lupposed that the 

 ground water flows in a regular stream along this 

 impervious stratum, for it does not. It fills all the 

 spaces in the soil lying directly above the stratum, and 

 drains gradually toward- the ipring (Kg, 11). We 

 have, then, is shown in the figure, first, a layer of soil 

 containing only film moisture, then a layer of wet soil, 

 containing free or ground water, and, finally, the 



Pio. II.— Water table in soil, a ft. surface of groun'. 

 ■Oil containing film moisture; /), soil containing free 

 water; K, Impervious stratum ; 8, spring; if, stream; W, 

 well . x r, line of water table. 



impervious layer. The digging of a well proves the 

 truth of these statement-: the well first panes through 

 a comparatively dry soil which carries only film 

 moisture. Finally, the well reaches a layer of soil 

 which is wet, and as it sinks into this layer it fills with 

 water to the point where the wet soil hegins. If carried 

 deep enough, helow this wet soil will be found a layer 

 of hard clay or stone. There ii usually a well mi 

 line where the soil containing- film moisture ends and 

 the free water begin*; the line s y : in Fig. 14 shows 

 where the change occurs, and it is called the water 



