[ 644 ] 
not be if contained either more or lefs fluid 
than that. 
PROP. XXVII. 
Let two bodies B and b (flg. 13.) be joined by a 
cylindric or prifmatic canal A filled with real 
fluid j and not by an imaginary canal of in- 
comprelfible fluid as in the 20th propofition ^ 
and let the fluid therein be in equilibrio; the 
force with which the whole or any given part of 
the fluid in the canal, is impelled in the dired;ion 
of its axis, by the united repullions and attradfi- 
ons of the redundant fluid or matter in the two 
bodies and the canal, muft be nothing; or the 
force with which it is impelled one way in the 
direction of the axis of the canal, muft be 
equal to that with which it is impelled the 
other way. 
For as the canal is fiippefed cylindric or prifmatic, 
no particle of fluid therein can prevented from 
moving in the dirc(flion of the axis of it, by the fides 
of the canal ^ and therefore the force with which 
each particle is impelled either way in the diredion 
of the axis, ‘by the united attradions and repulfions 
of the two bodies and the canal, muft be nothing, 
otherwife it could not be at reft ; and therefore the 
force with which the whole, or any given part of the 
fluid in the canal, is impelled in the diredion of 
the axfs, muft be nothing. 
3 
Cor o L. 
