PHYSICAL PARADOXES. 



converts it into a magnet, is probably in its turn 

 the production of a special form of vibration 

 in its small particles. 



Now, how can the vibrations in the soft iron, 

 which constitute it a magnet, act upon some- 

 thing at a distance so as to make it tend to 

 come nearer ? Is it by a pulling force which, 

 acting between them, and between them only, 

 draws them together, or is it by means of 

 pushing forces which, indirectly excited to act 

 in their rear, push them together from behind ? 



There are no proofs on this head, but there 

 are three lines of indication as to the probabili- 

 ties, and they all point in one way. 



Firstly, there are the cases which are analo- 

 gous in their gross or general character, such 

 as have already been referred to : the cases 

 of mechanical suction, of which we clearly 

 understand the action in detail. These cases 

 of apparent pulling at a distance all prove, on 

 careful examination, to be cases of indirect or 

 circuitous pushing. 



Secondly, the other vibrations, whose nature 

 in exact detail may be unknown to us, but whose 

 manner of action we understand, appear to 

 convey the same suggestion. It is generally 

 accepted that the mechanism by which heat 

 influence is transmitted is the delivery of a 

 series of blows that is, repulsion strokes by 

 the vibrating molecules of the hot substance 

 upon those of an adjacent substance or upon 



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