68 The Higher Usefulness of Science 



the molecules to become magnets actually realized? 

 Why, under the conditions imposed not by the mole- 

 cules taken by themselves, but by their relation to the 

 whole set of molecules constituting the particular mag- 

 netizable body. On the assumptions of the molecular 

 hypothesis, the degree of polarity of the molecules de- 

 pends upon their position in the magnet as a whole. 

 A molecule, a, for example, situated so near the middle 

 of a bar magnet that its assumed magnetic axes are 

 diverted very little from their in-all-directions condi- 

 tion, becomes at once, when the bar is broken, almost 

 entirely converted into north-south or south-north 

 axes, depending on whether the molecule is situated on 

 the north or south side of the break. The same mole- 

 cule may become one or another kind of magnet, de- 

 pending upon the whole magnet of which it is a part. 

 In other words the explanation, on the basis of the 

 molecular theory of magnetism, of the genesis of one 

 magnet from another by division, is seen on analysis 

 to depend not on the exclusively inherent powers of 

 the molecules, but on their interrelational powers and 

 also on their mass powers, that is, powers which they 

 possess in virtue of belonging to the particular magnet 

 to which they do belong. In reality the molecular 

 theory of magnetism is an attempted explanation of 

 the molecules of magnetizable substances based on 

 what magnets are, rather than an explanation of the 

 magnet based on what the molecules are; and the only 

 real merit the theory has is that it facilitates the 



