236 



E. C. ANDREWS. 



If the confluent streams be of equal strength and their 

 axes be arranged symmetrically to that of the main stream, 

 then the basin will be disposed symmetrically to the valley 

 walls and the action on the high bounding valley walls will 

 be similar [Fig. 5 (a)]. 



Fig. 5. 



(a) Illustration of general 



direction of stream 

 at a constriction 

 formed at a canon 

 confluence, each 

 feeder beingof equal 

 strength and equ- 

 ally inclined to the 

 main stream. 



(b) Confluence of two 



streams of variable 

 strength Q being 

 greater than P. R 

 marks the direction 

 of greatest stream 

 strength. 



(c) Streams of un- 

 equal strength 

 joining at ac- 

 cordant grades. 



