Chap. 2.] Conductors and Ntn- conductors. 313 



tricity remains at or near the end or part prefented, 

 without being communicated to the reft of the body, 

 it is called a non-conductor or electric ; but if, on the 

 contrary, the electricity is communicated to every 

 part, the body is called a conductor, or non-electric. 

 A body is faid to be infulated when it communicates 

 with nothing but electrics. 



A conductor cannot be electrified while it commu- 

 nicates with the earth, either by direct contact or by 

 the interpofition of other conductors, becaufe the elec- 

 tricity is immediately conveyed away to the earth. 



A mutual attraction is exerted between a body in a 

 ftate of electricity and all non-electric bodies, which, 

 if not large and heavy, wi,ll pafs rapidly through the 

 air to the electrified body, where they remain till they 

 have, by communication, acquired the fame ftate, 

 when they will be repelled. If aa uninfulated con- 

 ductor is at hand, it will attract the fmali body when 

 electrified, and deprive it of its electricity, fo that it 

 will be again attracted by the electrified body, and re- 

 pelled as before, and will continue to pafs and repafs 

 between the two, till the electric ftate is entirely de- 

 ftroyed. 



The following fubftances are reckoned among the 

 principal conductors of the electric fluid: 



Stony fubftances in general, 



Lime-ftone, marbles, 



Oil of vitriol, 



Allum, 



Black pyrites, 



Black lead in a pencil, 



Charcoal, 



All kinds of metals and ores, 



The fluids .of animal bodies, 



All fluids, except air and oils. 



Electric 



