A HISTORY OF SCIENCE 



ing this principle to the various experiments of elec- 

 tricity, one will be surprised at the number of obscure 

 and puzzling facts that it clears up. For Mr. Hauks- 

 bee's famous experiment of the glass globe, in which 

 silk threads are put, is a necessary consequence of it. 

 When these threads are arranged in the form of rays 

 by the electricity of the sides of the globe, if the finger 

 be put near the outside of the globe the silk threads 

 within fly from it, as is well known, which happens 

 only because the finger or any other body applied near 

 the glass globe is thereby rendered electrical, and 

 consequently repels the silk threads which are en- 

 dowed with the same quality. With a little reflection 

 we may in the same manner account for most of the 

 other phenomena, and which seem inexplicable with- 

 out attending to this principle. 



"Chance has thrown in my way another principle, 

 more universal and remarkable than the preceding one, 

 and which throws a new light on the subject of elec- 

 tricity. This principle is that there are two distinct 

 electricities, very different from each other, one of 

 which I call vitreous electricity and the other resinous 

 electricity. The first is that of glass, rock-crystal, pre- 

 cious stones, hair of animals, wool, and many other 

 bodies. The second is that of amber, copal, gum- 

 sack, silk thread, paper, and a number of other sub- 

 stances. The characteristic of these two electricities 

 is that a body of the vitreous electricity, for example, 

 repels all such as are of the same electricity, and on 

 the contrary attracts all those of the resinous electric- 

 ity; so that the tube, made electrical, will repel glass, 

 crystal, hair of animals, etc., when rendered electric, 



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