[ 221 3 
* . 
it follows, that the Fibres of the Feather will conti- 
nue to be attra&ed by it. 
Exp. IX. w . 
Take two Plates of Metal, very clean and dry, 
whofe Surfaces are nearly equal j hang one of them 
horizontally to the electrified Rod, and bring under 
it upon the other anythin light Body, as Leaf-Silver, 
&c. when the upper Plate is made electrical, the 
Silver will be attracted by it ; and if the under Plate 
is held at a proper Diftance, will be perfectly fuf- 
pended at right Angies to the Plates, without touch- 
ing either of them j but if they are either brought 
nearer together, or carried farther afunder, the Leaf- 
Silver will ceafe to be fulpended, and will jump up 
and down between them. The fame Effect will be 
produced, if you reverfe the Experiment, by electri- 
fying the bottom Plate, and fufpending the other 
over it. 
If the upper Plate is electrified when the Leaf- 
Silver is brought near, it will be attracted upwards 
by it, and thereby become electrical ; and fo long 
as it continues to be electrical, it will likewife be 
attracted downwards by the non electrical Plate. 
Whenever therefore this laft Attraction added to the 
Gravity of the Silver, which acts in the fame Di- 
rection, is equal to the contrary Attraction upwards, 
the Leaf-Silver will, by means of thefe two oppo- 
fite Forces, be kept fufpended between the Plates, 
and will continue to be fo, as long as the Equality 
of thefe Forces is preferved. 
F f z I have 
