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aperture E F ; and fince the water is continually accelerated 

 from the upper furface to the bottom, where it is difcharged, 

 by the adion of gravity, the body of defcending water will 

 contra<Sl in breadth according as the velocity encreafes, fo as to 

 move in a regular curve AKE, v/hich he calls the catarad of 

 defcending water. And becaufe the water, in its defccnt, fuffers 

 no other refiftance than what arifes from the fridion or mutual 

 adhefion of the particles, which in the prefent cafe is fuppofed 

 evanefcent, it follows, that the particles will defcend to the hole 

 with a velocity uniformly accelerated, and confequently that their 

 velocity in the aperture will be the fame as if they had defcended 

 in the vertical line H G. Now becaufe at the very inftant that 

 the water flows from the aperture the furface A B fubfides, 

 and the water is fupplied as faft at that furface as it iffues 

 from the orifice, it follows, that by difcovering the velocity with 

 which the water is poured in at A B to fupply the wafte, the 

 velocity with which it iffues from the orifice will be alfo afcer- 

 tained. For fuppofe I H to be the height from which a body 

 muft fall in order to acquire the velocity with which the water is 

 poured in, fince it is uniformly accelerated from thence to 

 the orifice by the adion of gravity, it follows, that the velocity 

 of the effluent water will be that which a heavy body would 

 acquire in falling down the height I G. 



He then proceeds to calculate the height I G -, and if S denote 

 the furface of the water at A B, A the orifice, and H the height 

 of the water, he fhcws that I G will be equal to the quantity 



But 



