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any lateral preffure in the water which is on a level with mn ; for 

 it is manifeft, that if an aperture were made in w B or ?iC, the 

 velocity of the water ifTuing through it would not be affedted by , 

 the infertion of the pipe; and confequently that the plate w«, 

 which is immediately in the orifice of the pipe, is the only one, 

 on the fame level, whofe tendency downwards is increafed by 

 the infertion of the pipe. Hence, the particles of water at the edge 

 of the aperture, having their perpendicular preffure encreafed by 

 the weight of the column vmrs, without any increafe of their, 

 lateral preffure, they will iffue through the orifice ?nn more per- 

 pendicularly ; the fides alfo of the tube will obftrud the con- - 

 verging motion of the particles, and confequently, on both thefe 

 accounts, the quantity of water difcharged through a pipe thus 

 inferted, will exceed that difcharged through a fimple orifice, in 

 a greater ratio than the fub-duplicate of the height of the water. , 

 And according as the length of the pipe encreafes, the ratio of O' 



the quantity of water adually difcharged by experiment, to that 

 which fhould be difcharged according to theory, will increafe ; 

 becaufe the ratio of the perpendicular to the horizontal preffure 

 increafes, in the ratio of the fum of the depth of the veffel and 

 length of the pipe, to the depth of the veffel. It follows therefore, 

 that experiments made in this manner, will approach nearer to 

 coincidence with theory, than when made with a fimple orifice j 

 except either when the tube is fo long as that the fri<flion of the 

 fluid againft the fides of the tube (hall produce a fenfibleeffed, or 

 Vo.L. VII. I . when . 



m 



