288 THE INTELLECTUAL RISE IN ELECTRICITY. 



remains, or may be rendered, magnetic. Lodestone is the 

 same body concreted with a stony Matter; and both mag- 

 netized iron and lodestone conform themselves to the globe 

 of the earth. 



So much for the hypothesis, fanciful enough in itself, 

 and yet, if not directly leading to Gilbert's practical dis- 

 coveries, at least not serving to conduct the investigator 

 directly away from them, as many an older 

 assumption had done. 



There is no perspective in Gilbert's record 

 of these researches save that leading to his 

 supposed magnetic proof of the Copernican 

 doctrine. Hence the difficulty in disentang- 

 ling from his often prolix restatements the 

 really novel and important achievements. 

 His own attempt to do this by marking large 

 asterisks beside the descriptions in his book 

 of those experiments which he regards as of 

 more importance is of little aid, since this 

 does not imply that the matters noted are of 

 his own inception, and, in some instances, 

 they are plainly taken from Porta. Neverthe- 

 less, it is possible to distinguish, as probably 

 original with Gilbert, the following remarka- 

 ble discoveries in magnetism : 



That the strength of a magnet can be aug- 

 mented and preserved by placing upon its 

 pole an iron helmet or cap the effect, as now 

 regarded, being to collect and converge the 

 GILBERT'S lines of force. This was the first suggestion 

 LOD^TONEs. 1 f ^ e armature or keeper. 



That the magnetic attraction will not be 

 cut off by any substance except, as he says, by an iron plate. 

 That the earth is a huge magnet, and has magnetic 

 poles. 



That the compass needle is directed by the earth's mag- 



1 From the first edition of his treatise De Magnete. 



