49 



CHAPTER I. 

 DISCOVERY OF LAWS OF MAGNETIC PHENOMENA. 



fTlHE history of Magnetism is in a great degree 

 JL similar to that of Electricity, and many of the 

 same persons were employed in the two trains of 

 research. The general fact, that the magnet attracts 

 iron, was nearly all that was known to the ancients, 

 and is frequently mentioned and referred to ; for 

 instance, by Pliny, who wonders and declaims con- 

 cerning it, in his usual exaggerated style 1 . The 

 writers of the stationary period, in this subject as 

 in others, employed themselves in collecting and 

 adorning a number of extravagant tales, which the 

 slightest reference to experiment would have dis- 

 proved ; as, for example, that a magnet when it has 

 lost its virtue, has it restored by goat's blood. Gil- 

 bert, whose work De Magnete we have already 

 mentioned, speaks with becoming indignation and 

 pity of this bookish folly, and repeatedly asserts the 

 paramount value of experiments. He himself, no 

 doubt, acted up to his own precepts; for his work 

 contains all the fundamental facts of the science, so 

 fully examined indeed, that even at this day we 

 have little to add to them. Thus, in his first Book, 

 the subjects of the third, fourth, and fifth Chapters 

 are, that the magnet has poles, that we may call 



1 Hist. Nat. lib. xxxvi. c. 25. 

 VOL. III. E 



