180 



ferent bodies in either of these cases, it is an invariable 

 rule, that glass, wax, rosin, brimstone, silk, hair, and 

 such like bodies, resist the most : and next to these, the 

 air, provided it be dry, and in a sufficient quantity. 

 Tiiat this resistance is least in metals, minerals, water, 

 animals,, and vegetables, which we may rank together, 

 because the difference in their resistance is very incon- 

 siderable : and that in these bodies the resistance is 

 greater, when their surfaces are polished,, and extended 

 in length, that when their surfaces are rough and short, 

 or end in sharp points. 



When a body has more electric fire forced into it, 

 than it has naturally, it is said to be electrified posi- 

 tively. When part of the natural quantity is taken 

 away, it is, said to be electrified negativety. Now when 

 an iron bar is negatively electrified, the fire drawn out 

 does not go in again as soon as the experiment is over, 

 but forms an atmosphere round it, because of the re- 

 sistance it finds in its endeavour to dilate itself, either 

 into the air, or into the bar. And when it is electrified 

 positively, the same kind of atmosphere is formed by 

 the fire accumulated upon it. Whether therefore bodies 

 are electrified negatively or positively* and remain so 

 when the experiment is over, there are similar atmos- 

 pheres surrounding them, which, will produce similar 

 effects. 



But we can electrify no body beyond a certain de- 

 gree ; because when any is electrified to that point, it 

 has an atmosphere round it sufficiently strong to balance 

 any power that endeavours to electrify it farther. 



And in the ordinary course of nature this subtle, 

 active fluid, which not only surrounds every gross body, 

 but every component particle of each, whore it is not 

 ill absolute contact with its neighbouring particle* can 

 never be idle, but is ever in action, though that action 

 be imperceptible to our senses. Jt is ever varying its 

 condition, though imperceptibly, in ail parts of ail 

 bodies whatever; and electrifying them more or less, 

 though not.so forcibly as to give sensible signs of it 



