TRIANGULAR ORIFICE IN THE SIDE Of A VESSEL. 153 



COB. 2. If the orifice be a triangle DCH (Fig. 41), 

 whose base DC = b l is situated at a depth KL = 7/ t be- 

 low the surface of the liquid, and whose vertex H is at a 

 depth h below the surface, the discharge is equal to that 

 through the triangle AHB, minus that through the trap- 

 ezoid ABCD. Hence, from (3) and (5), we have 



Q = 



Since AB : DC :: HK : HL, we have 

 b : l) l :: // : h h l ; 



(6) 



which in (6) gives 



Q = 



15 



h 



COR. 3. If the orifice be a triangle ABC, 

 whose vertex A is above its base, and at a 

 depth ^! below the surface of the liquid, 

 whose base CB = 5 X is at a depth h below 

 the surface, the discharge is equal to that 

 through the rectangle ACBK, minus that 

 through the triangle ABK. Hence, from 

 (7) and (4) of Art. 85, we have 



g = , (* _,,!)- 



(7) 



Fig. 42 



_ 2V_Ji / 

 ~ 15 \ 



