4 ELEMENTS OF STATIC ELECTRICITY. 



The first fact was shown when the pith ball, after 

 contact with the wax, attracted and electrified the 

 other pith ball ; and the second fact by the repulsion 

 of the pith ball from the wax after contact ; then of 

 ther two pith balls from each other and from the wax, 

 after contact ; and finally by the mutual repulsion of the 

 balls, without previous attraction, after being separately 

 electrified by the wax. 



This series of phenomena may be produced by using 

 a glass or ebonite rod, or any of the substances already 

 mentioned, as well as by the sealing-wax ; showing that 

 repulsion as well as attraction is a property common to 

 all electrified bodies. 



CONDUCTORS AND NON-CONDUCTORS. Pursuing our 

 investigation, new properties are developed. It is 

 found that while certain substances, as glass, ebonite, 

 and sealing-wax, show electric qualities, others, as brass, 

 iron, and copper, apparently do not show such qualities. 

 This led to the old division of all substances into 

 electrics^ a term applied to the former, and non-electrics, 

 applied to the latter. 



But more thorough investigation has proved that 

 electricity may be generated by friction on the brass, 

 iron, and copper, as well as on the glass, ebonite, and 

 sealing-wax ; but that, when generated on bodies of the 

 former class, it is instantly distributed over the entire 

 body, and escapes to the earth unnoticed, if the body 

 be held in the hand, while, when generated on bodies 

 of the latter class, it is not so distributed, and does not 

 pass off in this way; bodies of the former class allowing 

 free electric movement, over the surface or through the 

 mass, while those of the latter class resist such move- 

 ment. 



