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mutual attraaion, by the interior filaments whofe velocity is 

 greater ; whence there follows a diminution in the diameter of 

 the vein. 



This manner of accounting for the contradion of the vein 

 feenis more reafonable than that which is given by Newton ; as 

 there appears to be no adequate caufe for the acceleration of 

 the water, after it has been difcharged from the orifice. 



The diminution of the mean velocity of the water, caufed 

 folely by the obliquity of the motions of the ifFuing particles, 

 exclufive of any other impediment, may be thus determined : 



Let 77171 (fig. I.) be the diameter of the aperture in the vefl'el 

 ABDC filled with water: in whatever diredion the water 

 iffues, its velocity in that diredion will, in all cafes, be the fame, 

 becaufe the preffure of fluids is the fame in all diredions j thus', 

 whetlier a fluid fpouts perpendicularly upwards or downwards,' 

 horizontally or obliquely, the fpace through which it is projeded,' 

 in a given time, is the fame. Now to determine this diredion,' 

 fince the horizontal and vertical prefigures are equal, the ifl"uing' 

 particles will affume the intermediate diredion, which will 

 therefore form an angle of 45°. with the plane of the orifice : its 

 vertical velocity therefore will be lefs than its dired or total 

 velocity in the proportion of the diagonal of a fquare to its fide, 



or 



