CONDUCTORS AND INSULATORS. 



211 



CONDUCTING BODIES IN ORDER OF 

 CONDUCTING POWER. 

 Metallic ores. 

 Animal tluids. 

 Sea-water 

 Spring-water. 

 Rain-water. 

 Ice above 13 Fahr. 

 Snow. 



Living vegetables. 

 Living animals. 

 Flame smoke. 

 Steam. 



Salts soluble in water. 

 Rarefied air. 

 Vapour of alcohol. 

 Vapour of ether. 

 Moist earth and stones. 

 Powdered glass. 

 Flowers of sulphur. 



The following may be added to the Insulators, viz. : 



Sulphur. 



Resins. 



Amber. 



INSULATORS IN THE INVERSE ORDER OF 

 INSULATING POWER. 

 Dry chalk. 



Native carbonate of baryta. 

 Lycopodium. 

 Caoutchouc. 

 Camphor. 



Silicious and argillaceous stones. 

 Dry marble. 

 Porcelain. 

 Dry vegetables. 

 Baked wood. 

 Leather. 

 Parchment. 

 Dry paper. 

 Hair. 

 Wool. 

 Dyed silk. 

 Bleached silk. 

 Raw silk. 



Transparent precious stones. 



Diamond. 



Mica. 



All vitrefactions. 



Glass. 



Jet. 



Wax. 



Gutta-percha. 

 Shell-lac (or gum-lac). 

 Ebonite. 



There are, as we know, two kinds of electricity, the static and dynamic ; 

 and when the latter state is instantaneous, it is referred to as the " electric 

 discharge," which occurs when opposite electricities seek each other, and the 

 bodies return to a state of equilibrium or neutralization. " These bodies, if 

 insulated, obtain no more electricity after the spark has passed ; but if there 

 be a constant source of negative electricity supplying one, and a constant 

 source of negative electricity supplying the other, there will be a succession 

 of sparks ; and if they communicate by a conductor there will be, through 

 this conductor, an uninterrupted neutralization of a continual reunion of the 

 two electricities, and this is what is termed the continuous dynamic state or 

 electric current " (Dc la Rive), 



