176 PROF. OSBORNE REYNOLDS ON 



•■•"=^/^"^;-:{'-C^)"} (3. 



'>='i^& ■ • • • • • (^) 



Hence along a steady stream, since W is constant, 

 equation (5) gives a relation that must hold between A 

 and JO. 



Differentiating A with respect to p and making -7— zero, 



it appears 



y-i Y-» 



2/>x y =(7+1)? y , .... (6) 

 or 



£ = (-^V-^. ...... (7) 



For air 7=1-408. 



•••^=■5^7 • • . (8) 



It thus appears that as long as p falls, the section con- 

 tinuously diminishes to a minimum value when jo = '527jOj, 

 ~ and then increases again. Substituting this value of p in 

 equation (3), 



--V^^iT^j^j • • • ^^^ 



=^./ 2Wo /M'-g .... (10) 

 Hence by equation (6), 





(12) 

 7oTo ^ 



