GALILEO AND THE NEW PHYSICS 



the loadstone on a float in water, and observed that 

 the poles always revolved until they pointed north and 

 south, which he explained as due to the earth's mag- 

 netic attraction. In this same connection he noticed 

 that a piece of wrought iron mounted on a cork float 

 was attracted by other metals to a slight degree, and 

 he observed also that an ordinary iron bar, if suspended 

 horizontally by a thread, assumes invariably a north 

 and south direction. These, with many other experi- 

 ments of a similiar nature, convinced him that the 

 earth "is a magnet and a loadstone," which he says is 

 a "new and till now unheard-of view of the earth." 



Fully to appreciate Gilbert's revolutionary views 

 concerning the earth as a magnet, it should be remem- 

 bered that numberless theories to explain the action 

 of the electric needle had been advanced. Columbus 

 and Paracelsus, for example, believed that the magnet 

 was attracted by some point in the heavens, such as 

 a magnetic star. Gilbert himself tells of some of the 

 beliefs that had been held by his predecessors, many 

 of whom he declares "wilfully falsify." One of his 

 first steps was to refute by experiment such assertions 

 as that of Cardan, that "a wound by a magnetized 

 needle was painless " ; and also the assertion of Fracas- 

 toni that loadstone attracts silver ; or that of Scalinger, 

 that the diamond will attract iron ; and the statement 

 of Matthiolus that "iron rubbed with garlic is no 

 longer attracted to the loadstone." 



Gilbert made extensive experiments to explain the 

 dipping of the needle, which had been first noticed by 

 William Norman. His deduction as to this phenomenon 

 led him to believe that this was also explained by the 



