Canon Moseley on the steady Flow of a Liquid. 45 



WTien the pipe was full and before 

 its top was removed. 



Section of stream 0*5 X 0-8 metre. 



Slope per metre 0-00427 metre. 



Discharge per sec. 0*618 m. c. 



Section of stream 0-3 X 0-48metre, 



Slope per metre 0-00627 metre. 



Discharge per sec. 0-191 m. c. 



When the pipe was half full and 

 after its top was removed. 



Section of stream 0-2458 X 0-8 met, 

 Slope per metre 0-0043 metre. 

 Discharge per sec. 0307 m. c 



Section of stream 0-1513x0-48 m. 

 Slope per metre 0-006 metre. 

 Discharge per sec. 0093 m. c. 



Discharge from an open channel of any form. 



If, then, Q be taken to represent the discharge from an open 

 rectangular channel half filled, 2Q will represent that from the 

 same channel having its section doubled and being closed and 

 filled. If, then, we take c, as before, to represent the depth of 

 the stream, and h its breadth, and substitute 2Q for Q in equa- 

 tion (60), and 2c for c, the resulting value of Q will be that of 

 the discharge from an open rectangular channel. 



Moreover the reason for the discharge from an open rectan- 

 gular channel being half that from a closed one of double the 

 section applies equally to channels of all other forms, so that 

 the fact of the half discharge being obtained from the open 

 channel of half the section of the closed one may be assumed to 

 be generally true. If therefore we substitute 2Q for Q in equa- 

 tion (54), 2% for y^, 2X1 for O, we shall obtain a formula in 

 which Q represents the discharge from an open channel of any 

 given form, XI representing the section of the stream, and i^ the 

 wetted periphery of the section of the channel. We thus obtain 

 from equation (54) an equation for the discharge from an open 

 rectangular channel. 



By equation (60), 



Q= 



(6 + 2c)' 

 %rfhc 



{■-(>n^.> 





(63) 



By equation (61), 



(g^z.*(6+2c) 



27^M(6c)^ V ^^-^^ ^ 



65-J73(Z> + 2c)^^ Ml 2yhc 



Q= 





.)(si 



I Usinzl 



(64) 



For the discharge from a uniform open channel of any given 



