C 36 1 



When a piece of sealing-wax is rubbed by a 

 woollen cloth, it gains the power of attracting light 

 bodies, such as feathers or ashes. In this state it is 

 said to be electrical ; and if a metallic cylinder, placed 

 upon a rod of glass, is brought in contact with the 

 sealing-wax, it likewise gains the momentary power of 

 attracting light bodies, so that electricity like heat is 

 communicable. When two light bodies receive the 

 same electrical influence, or are electrified by the 

 same body, they repel each other. When one of them 

 is acted on by sealing-wax, and the other by glass that 

 lias been rubbed by woollen, they attract each other ; 

 hence it is said, that bodies similarly electrified repel 

 each other, and bodies dissimilarly electrified attract 

 each other : and the electricity of glass is called 

 vitreous or positive electricity, and that of sealing-wax 

 resinous or negative electricity. 



W hen of two bodies made to rub each other one 

 is found positively electrified, the other is always 

 found negatively electrified, and, as in the common 

 electrical machine, these states are capable of being 

 communicated to metals placed upon rods or pillars of 

 glass. Electricity is produced likewise by the contact 

 of bodies ; thus a piece of zinc and of silver give a 

 slight electrical shock when they are made to touch 

 each other, and to touch the tongue : and when a 

 number of plates of copper and zinc, 1 00 for instance, 

 are arranged in a pile with cloths moistened in salt and 

 water, in the order of zinc, copper, moistened cloth, 

 zinc, copper, moistened cloth, and so on, they form 

 an electrical battery which will give strong shocks 



