ELECTRICITY. 335 



Set the mill near the prime conductor, and place 

 the crooked wire, so that its point may be directed 

 towards the uppermost side of the great wheel A. 

 Then turn the glass globe by the winch, and the 

 stream of fire that issues from the point of the wire 

 will turn the wheel ; and, consequently, all the 

 other working parts of the mill. 



Of the Ley den Phial, and the Electrical Shock . 



When an electric or non-conducting body is 

 presented to a body containing a super-abundant 

 quantity of electricity, the opposite sides of the 

 electric become possessed of different kinds of 

 electricity j that is, one is positive, and the other 

 negative. Thus, if a plate of glass be brought 

 into contact with the prime conductor, or if a 

 point from the prime conductor be made to touch 

 the glass, one side of the glass becomes posi- 

 tive and the other negative. In this case the 

 glass is said to be charged ; and the two kinds of 

 electricity cannot come together to restore the 

 equilibrium, because of the non-conducting quality 

 of the glass. 



But if a communication be made between the two 

 sides of the glass by means of a conducting sub- 

 stance, then a discharge will take place from one 

 to the other, the electricity passing through the 

 conducting body. This discharge is called the 

 electric shock : because when a living animal forms 

 part of the communication between the two sides 

 of the charged plate, so that the discharge must 

 pass through it, a sudden shock or peculiar sens- 

 ation is felt. 



