326 DISCOURSE ON THE STUDY 



wire of any metal indifferently all the properties of 

 a magnet; its attraction, repulsion, and polarity; 

 and that even in a more intense degree than was pre- 

 viously thought to be possible in the best natural 

 magnets. In short, in this case, and in this case 

 only, perhaps, in science, have we arrived at that 

 point which Bacon seems to have understood by the 

 discovery of " forms." " The form of any nature," 

 says he, " is such, that where it is, the given nature 

 must infallibly be. The form, therefore, is perpe- 

 tually present when that nature is present ; ascer- 

 tains it universally, and accompanies it every where. 

 Again, this form is such, that when removed, the 

 given nature infallibly vanishes. Lastly, a true form 

 is such as can deduce a given nature from some 

 essential property, which resides in many things." 



(365.) Magnetism is remarkable in another im- 

 portant point of view. It offers' a prominent, or 

 " glaring instance" of that quality in nature which 

 is termed polarity (267.), and that under circum- 

 stances which peculiarly adapt it for the study of 

 this quality. It does not appear that the ancients 

 had any knowledge of this property of the magnet, 

 though its attraction of iron was well known to them. 

 The firsf mention of it in modern times cannot be 

 traced earlier than 1180, though it was probably 

 known to the Chinese before that time. The po- 

 larity of the magnet consists in this, that if sus- 

 pended freely, one part of it will invariably direct 

 itself towards a certain point in the horizon, the 

 other towards the opposite point ; and that, if two 

 magnets, so suspended, be brought near each other, 

 there will take place a mutual action, in consequence 



