on the EleBrophorus. 1039 
in this atmofphere be of a fmall extent, it will be found 
fo to all appearance, becaufe the two extremities of a 
fmall body cannot be feparately examined; whereas a 
body of a certain extent exhibits in a very perceptible 
manner the two diftinci electricities. The real'on of this 
wonderful phenomenon is to be underftood by the prin- 
ciples adopted, and may without much attention be un- 
derftood, if we luppofe the excited body to be in a pofi- 
tive ftate of eledtricity; for in this cafe the atmofphere 
of eleCtric fluid furrounding the excited body forces by 
its repulfive quality the eleCtric fluid of the neighbour- 
ing body towards its farthermoft extremity, and thus ac- 
cumulates or crouds it upon that extremity, from which 
extremity it is therefore ready to fly off upon any other 
body, which is of a nature to receive it, being brought 
near enough. 
If the excited body be in a ftate of negative electricity, 
the explanation is not fo obvious as in the pofitive cafe : 
it requires fome more attention to conceive what pafles. 
The excited body, having loft a part of its natural lhare 
of eleCtric fluid, a kind of vacuum, if I may call it fo, 
takes place upon this body. The eleCtric fluid of any 
other body being in its natural ftate, and therefore in a 
kind of inactivity, confined as it were within its limits 
by the eleCtric fluid of all the furrounding bodies, is fet 
at 
