THE MECHANICO-CHEMICAL SCIENCES. 7 



of Physical Astronomy. And we shall, in the first 

 part of our account, not dwell much upon the 

 peculiar conditions under which bodies are mag- 

 netic or electric, since these conditions are not 

 readily reducible to mechanical laws; but, taking 

 the magnetic or electric character for granted, we 

 shall trace its effects. 



The habit of considering magnetic action as the 

 type or general case of attractive and repulsive 

 agency, explains the early writers having spoken of 

 electricity as a kind of magnetism. Thus Gilbert, 

 in his book De Magnete (1600), has a chapter 1 , 

 De coitione Magneticd, primumque de Succini at- 

 tractione, sive verius corporum ad Succinum appli- 

 catione. The manner in which he speaks, shows 

 us how mysterious the fact of attraction then ap- 

 peared; so that, as he says, "the magnet and 

 amber were called in aid by philosophers as illus- 

 trations, when our sense is in the dark in abstruse 

 inquiries, and when our reason can go no further." 

 Gilbert speaks of these phenomena like a genuine 

 inductive philosopher, reproving 2 those who before 

 him had " stuffed the booksellers' shops by copying 

 from one another extravagant stories concerning 

 the attraction of magnets and amber, without giving 

 any reason from experiment." He himself makes 

 some important steps in the subject. He distin- 

 guishes magnetic from electric forces 3 , and is the 

 inventor of the latter name, derived from ^Xe/cr/ooi/ 

 electron, amber. He observes rightly, that the 



1 Lib. ii. cap. 2. 2 De Magnete, p. 48. 3 Ib. p. 52. 



