{ 624 ] 
intlrely deprived of it j and the fluid within the 
fpace f gh will be dlfpofed very nearly fimilarly 
to that ill the fpace F G H. 
For it is plain, that if the fluid could be difpofed 
accurately in a fimilar manner in both bodies, the 
fluid would be in equilibrio in one body, if it was in 
the other : therefore draw the furface /SS g, fuch that 
the thicknefs of the fpace /8 f fliall be every where 
to the correfponding thicknefs of B F, as the dia*- 
meter of hd e to the diameter of BDE j and let the 
1 -edundant fluid or matter in be fpread uniformly 
over the fpace jG f\ then if the fluid in the fpace fgh 
■is difpofed exadlly fimilarly to that in FGH, it will 
be in equilibrio j as the fluid will then be difpofed 
exafUy fimilarly in the fpaces and BDE : but 
as by the fuppolition, the thicknefs ofxthe fpace ^ f 
is very fmall in refpedfc of the diameter of bde^ the 
fluid or matter in the fpace b f will exert very nearly 
the fame force on the reft of the fluid, whether it is 
fpread over the fpace jSyi or whether it is colledled 
in bj^ 
PROP, XVIII. 
Let two bodies, B and b^ be connetft:ed to each 
other by a canal of any kind, and be either over 
or undercharged : it is plain that the quantity 
of redundant or deficient fluid in B, would 
bear exadlly the fame proportion to that in b^ 
whatever fort of matter B confifted of, if it was 
pofiible for the redundant or deficient fluid in 
i any 
