[ 656 ] 
fluid In B, tends to increafe the force with which the 
two bodies attrad:. 
Case VII. It IS plain that a non-conduding 
body faturated with fluid, is not at all attraded or 
repelled by an over or undercharged body, until, by 
the adion of the eledrified body on it, it has either 
acquired fome additional fluid from the air, or had 
fome driven out of it, or till fome fluid’ is driven from 
one /part of the body to the other. 
Case VIII. Let us now fuppofe that the two 
bodies A and B are both pofitively eledrified in the 
fame degree. It is plain, that were it not for the 
adion of one body on the other, they would both be 
overcharged, and would repel each other. But it 
may perhaps be faid, that one of them as A may, by 
the adion of the other on it, be either rendered un- 
dercharged on the whole, or at leaft may be rendered 
undercharged in that part nearefl: to B ; and that the 
attradion of this undercharged part on a particle of 
the fluid in B, may be greater than the repulfion of 
the more diftant overcharged part; fo that on the 
whole the body A may attrad a particle of fluid in 
B. If fo, it muft be affirmed that the body B repels 
the fluid in A ; for otherwife, that part of A which 
is nearefl: to B could not be rendered undercharged. 
Therefore, to obviate this objedion, let the bodies be 
joined by the ftraight canal DC of incompreffiblc 
fluid (fig. 1 9.). The body B will repel the fluid in 
all parts of this canal ; for as A is fuppofed to attrad 
the fluid in B, B will not only be more overcharged 
than it would otherwife be, but it will alfo be more 
over- 
