VON GUERICKE ON ELECTRIC REPULSION. 397 



"Thus this globe when brought rather near drops of 

 water causes them to swell and puff up. It likewise at- 

 tracts air, smoke, etc. 



" From these experiments it must be seen that there ex- 

 ists in the earth for the preservation of itself a virtue of 

 this sort, which also can be excited in an especially 

 suitable body, namely, this globe, so that it acts more in 

 it than in the earth itself (for whatever this globe attracts, 

 it snatches it, as it were, or draws it away from the earth). " 



Now follows the first positive recognition of electric re- 

 pulsion which is none other than von Guericke's expul- 

 sive virtue. Cabaeus had seen the chaff leap back from 

 the electric, but he had not interpreted the phenomenon 

 itself, although he had tried to concoct a theory in con- 

 formity with it. Not so von Guericke. Hear him: 



"Even expulsive virtue is to be seen in this globe 

 (namely when it is taken from the apparatus to the hand 

 and is rubbed or stroked in said manner with the dry hand), 

 for it not only attracts but also repels again from itself 

 little bodies of this sort (in proportion to their temper), 

 nor does it receive them until they have touched some- 

 thing else." 



There is also the first suggestion of the discharge of the 

 electrification of the attracted body on contact with an 

 object other than the electric, and its consequent re-attrac- 

 tion by the latter. 



But note his experiment. He takes the globe out of its 

 supports and holds it in his hands with its axis vertical. 

 Then, after exciting the globe and causing it to repel a 

 feather, he carries it around the room, so that it drives 

 the feather, floating in the air, before it. His feather is a 

 bit of down, which he says "extends itself and in some 

 way shows itself alive" its individual electrified fila- 

 ments of course mutually repelling. He observes that 

 when it is thus chased around the room it prefers to ap- 

 proach u the points of any object whatsoever before it, and 

 it is possible to bring it where it may cling to the nose of 



