Chemical Theory of Electricity and Magnetism. 5 1 



jar, if the communicating wire has been quickly withdrawn, a second 

 small shock may be taken after the principal discharge, and this 

 repeatedly two or three times. 



Hence the charge of the Galvanic pile being very minute in quan- 

 tity or intensity, will not readily pass through the dry cuticle of the 

 hands, though it so easily passes through animal flesh or nerves, as 

 this combination of charcoal with water seems to constitute the most 

 perfect conductor yet known. 



9. As light is reflected from the surface of a mirror before it 

 actually touches it, and as drops of water are repelled from cabbage 

 leaves' without touching them, and as oil lies on water without touch- 

 ing it, and also as a fine needle may be made to lie on water without 

 touching it, as shown by Mr. Melville in the Literary Essays of Edin- 

 burgh; there is reason to believe, that the vitreous and resinous 

 electric ethers are repelled by, or will not pass through, the surfaces 

 of glass or resin, to which they are applied. But though neither 

 of these electric ethers passes through the surfaces of glass or resin, 

 yet their attractive or repulsive powers pass through them; as the 

 attractive or repulsive power of the magnet to iron passes through 

 the atmosphere, and all other bodies which exist between them. So 

 an insulated cork-ball, when electrised either with vitreous or resinous 

 ether, repels another insulated cork-ball electrised with the same 

 kind of ether, through half an inch of common air, though these 

 electric atmospheres tio not unite. 



Whence it may be concluded, that the general attractive and 

 repulsive ethers accompany the electric ethers as well as they accom- 

 pany all other bodies; and that the electric ethers do not themselves 

 attract or repel through glass or resin, as they cannot pass through 

 them, but strongly attract each other when they come into contact, 

 rush together, and produce an explosion of the sudden liberation of 

 heat and light. 



III. Effect of Metallic Points. 



1. When a pointed wire is presented by a person standing on the 

 ground to an insulated conductor, on which either vitreous or resinous 



