428 Flow of Water through fmall Apertures. [BookVII. 



rally. The tendency of the particles towards the aper- 

 ture is a neceflary confequence of their perfect mobi- 

 lity ; for they will certainly be directed towards the 

 point where there is the leaft refiftance, and that point 

 is the aperture. 



It is alfo to be obferved, that in this cafe, at a fmall 

 diftance from the bottom, a kind of funnel is formed 

 in the water, the point of which correfponds to the 

 center of the aperture j when, however, the water 

 flows through a lateral orifice or aperture, there is 

 formed only a kind of half funnel, which does not ap- 

 pear to commence till the fur face is near touching the 

 tipper fide of the hole. It is probable that the fun- 

 nel begins to form itfelf from the firft moment of the 

 8ow i but it 'does not become perceptible till the fur- 

 face is only at a final! diftance from the bottom. 



It appears alfo, that the funnel commences higher 

 or lower, according to the width of the bottom j and 

 that the formation of it is lefs prompt or lefs percepti- 

 ble, according to the proportion of the aperture to the 

 extent of the bottom. The funnel is alfo augmented 

 by any roughnefs which may exifl at the fides or bot- 

 tom of the veflel. 



Water flows out of a firtall hole in the bottom of a 

 vefTel with a velocity equal to that which a ponderous 

 body acquires* in falling from a hright equal to the 

 vertical height of the furface of the fluid above the 

 aperture. 



The fame law takes place in a lateral orifice j for 

 the prefliire of the fluid is equal (at the fame depth) 

 in all directions, and confequently produces the fame 

 degree of velocity. 



A fluid, in running out of an aperturp, acquires a 

 velocity fufScicnt to make it remount to a vertical 



height 



