462 RECAPITULATION. 



of electricity will force its way through the air, from 

 the latter to the former, appearing in the form of a 

 spark. 



11. When two bodies approach each other suffi- 

 ciently near, one of which is electrified positively, 

 and the other negatively, the superabundant elec- 

 tricity rushes violently from one to the other, to 

 restore the equilibrium between them. This effect 

 takes place, if the two bodies be connected by a 

 conducting substance. 



12. If an animal be placed so as to form part of 

 this circuit, the electricity, in passing through it, 

 produces a sudden effect upon it, which is called 

 the electric shock. 



13. The motion of electricity, in passing from 

 a positive to a negative body, is so rapid, that it 

 appears to be instantaneous. 



14. When any part of one side of a piece of 

 glass is presented to a body electrified positively or 

 negatively, that side becomes possessed of the 

 contrary electricity to the side of the body it is 

 presented to ; and the other side of the glass is 

 possessed of the same kind of electricity as the 

 other body. 



15. This electricity communicated to the glass 

 does not spread, but is confined to the part where 

 it is communicated, on account of the non-con- 

 ducting quality of the glass. 



16. To accelerate the communication, and to 

 enable it to be applied to the whole surface, 

 the glass is covered with tin-foil, which is called 

 coating the glass. 



17. If a conducting communication be made 

 between both of the sides of a glass so coated 

 and charged with electricity, a discharge takes 

 place. 



