A HISTORY OF SCIENCE 



distance, 'tis surprising to see how suddenly it flies back 

 to the tube. Points of wood will do as well as those of 

 iron, provided the wood is not dry; for perfectly dry 

 wood will no more conduct electricity than sealing-wax. 



"To show that points will throw off as well as draw 

 off the electrical fire, lay a long, sharp needle upon the 

 shot, and you cannot electrify the shot so as to make 

 it repel the cork ball. Or fix a needle to the end of a 

 suspended gun-barrel or iron rod, so as to point beyond 

 it like a little bayonet, and while it remains there, the 

 gun-barrel or rod cannot, by applying the tube to the 

 other end, be electrified so as to give a spark, the fire 

 continually running out silently at the point. In the 

 dark you may see it make the same appearance as it 

 does in the case before mentioned." 3 



Von Guericke, Hauksbee, and Gray had noticed that 

 pointed bodies attracted electricity in a peculiar man- 

 ner, but this demonstration of the "drawing off" of 

 "electrical fire" was original with Franklin. Original 

 also was the theory that he now suggested, which had 

 at least the merit of being thinkable even by non- 

 philosophical minds. It assumes that electricity is 

 like a fluid, that will flow along conductors and ac- 

 cumulate in proper receptacles, very much as ordinary 

 fluids do. This conception is probably entirely in- 

 correct, but nevertheless it is likely to remain a popular 

 one, at least outside of scientific circles, or until some- 

 thing equally tangible is substituted. 



Franklin's Theory of Electricity 



According to Franklin's theory, electricity exists in 

 all bodies as a " common stock," and tends to seek and 



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