146 STUDIES IN ELECTRO-PHYSIOLOGY: 



It will be useful at this stage to bear in mind certain 

 electrical laws 



(1) The amount of electricity induced by an electrified 



body on surrounding conductors is equal and 

 opposite to that of the inducing body. 



(2) Induction leads to discharge as well as charge. 



At contact, or within a distance bridgable by the 

 tension, the charge would be neutralised. 

 (8) Faraday called the medium through which induc- 

 tion is propagated, such as air, shellac, paraffin 

 wax, etc., the dielectric. Air is taken as 1 and 

 all other substances as more than 1. Air, there- 

 fore, is only a bad conductor, not a non- 

 conductor. 



(4) Faraday further supposed the particles or mole- 



cules of the dielectric to be conductors insulated 

 from each other ; and to this discovery we owe 

 the condenser, and the Farad as the unit of 

 capacity. 



(5) Induction propagates itself in the direction where 



it has the least resistance to encounter. 



(6) The charge that a body receives is always in 



proportion to the facilities it offers for induction. 

 If a body is so situated that it has nothing to act 

 on, it receives no charge, or, in other words, has 

 no inductive capacity. 



(7) Discharge begins where the tension is greatest. 



(8) The greater the surface over which electricity is 



diffused the less its tension at any particular 

 point, and vice versa. 



(9) Electricity is exhibited only on the surface of 



conductors. 



(10) The distribution of electricity on the surface of 

 insulated conductors is influenced materially by 

 their form. 



(11) Electricity concentrates on points and pro- 

 jections. 



