THE DISCOVERY OF ELECTRICAL REPULSION. 351 



facts, and he interprets them wrongly; but dissent from 

 Gilbert's hypothesis and the production of a new one in 

 supposed accordance with the new data were inevitable. 



What had he seen ? That, when the face of a well-pre- 

 pared electric is applied to the drawing of light filings or 

 sawdust or similar corpuscles, they run strongly to the 

 electric, and when they reach it they fly back, not falling 

 off merely, but being thrown off afar to a distance of two 

 or three inches. And that sawdust groups itself upon the 

 electric u like masses of hairs," the ends of which fluctuate 

 and waver, and finally these extremities likewise do not 

 fall off, but are projected afar. 



In brief, he had found electrical repulsion the phenom- 

 enon which Gilbert said had no existence. He had seen, 

 as any one may now see, the oppositely-electrified body 

 move to the electric, become similarly charged and fly away 

 from it. This plainly could not be accounted for by sup- 

 posing material arms or rods grasping the attracted body, 

 and in some unknown way bringing it to the electric; and 

 so Cabaeus framed a new hypothesis, wherein repulsion was 

 in fact the fundamental feature. The rubbed electric, he 

 avers, produces a most thin effluvium, which attenuates 

 the air and vigorously impels it; and this attenuated air, 

 in returning to the electric in a gyration, brings with it 

 the attracted * body. In other words, he thinks that efflu- 

 vium is first "expelled," and thereby the air is "propelled" 

 in a wind. The wind comes back, entraining with it the 

 chaff sometimes even with such violence that it seems to 

 rebound from the electric. Such was the first recognition 

 of electrical repulsion and the first theory proposed to ac- 

 count for it. 



It will be recalled that Gilbert says that the rays of mag- 

 netic force emanate in all directions from the lodestone's 

 centre, and thus form an "orb" or "sphere of virtue" 

 around "that great magnet, the earth." Herein he dif- 



