CIRCULATION OF WATER IN BELT OF CEMENTATION. 



573 



top or slope of a hill to a point of issue at the foot of a hill, supposing these 

 to be the only points of entrance or issuance of the water, and supposing 

 the spaces to be uniform, the vertical course would be represented by the 

 lines of fig. 9 and the horizontal course would be represented by the lines 

 of fig. 7. 



Fig. 9.— Ideal vertical section of the flow, through a homogene 

 on a slope and issuing at a lower point. 



medium, of ground water entering at 



• In an actual case of ground-water flowage the water does not enter the 

 ground at a single point, but at every point of a slope. As a simple case, 

 we may suppose that the water entering on a slope reaches the surface again 

 at the level of a stream in an adjacent valley. To get an idea of the com- 

 plexity of the flow in this ideal case we may arbitrarily select a number of 

 points where the water enters and trace out its course. We may plat by 



