A HISTORY OF SCIENCE 



very close to discovering the discharge of the electrifi- 

 cation of attracted bodies by contact with some other 

 object, after which they are reattracted by the electric. 



He performed a most interesting experiment with 

 his sulphur globe and a feather, and in doing so came 

 near anticipating Benjamin Franklin in his discovery 

 of the effects of pointed conductors in drawing ofl the 

 discharge. Having revolved and stroked his globe 

 until it repelled a bit of down, he removed the globe 

 from its rack and advancing it towards the now re- 

 pellent down, drove it before him about the room. 

 In this chase he observed that the down preferred to 

 alight against "the points of any object whatsoever." 

 He noticed that should the down chance to be driven 

 within a few inches of a lighted candle, its attitude 

 towards the globe suddenly changed, and instead of 

 running away from it, it now " flew to it for protection " 

 the charge on the down having been dissipated by 

 the hot air. He also noted that if one face of a feather 

 had been first attracted and then repelled by the sul- 

 phur ball, that the surface so affected was always turn- 

 ed towards the globe; so that if the positions of the 

 two were reversed, the sides of the feather reversed 

 also. 



Still another important discovery, that of electrical 

 conduction, was made by Von Guericke. Until his 

 discovery no one had observed the transference of 

 electricity from one body to another, although Gilbert 

 had some time before noted that a rod rendered 

 magnetic at one end became so at the other. Von 

 Guericke' s experiments were made upon a linen thread 

 with his sulphur globe, which, he says, "having been 



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