58 NOMOS. 



chemical virtues. The molecules may be composed 

 of very different substances, but they all agree in 

 that their corresponding elements are turned in the 

 same direction. In this, which is the essential point, 

 they are all similar) and being similar, what will be 

 their natural tendencies? This is the question. 

 Will they attract each other or will they not ? There 

 is no doubt that similar molecules under other cir- 

 cumstances will attract each other. When, for 

 example, two different kinds of salts are mixed 

 together in solution, we know that they will crys- 

 tallise separately, the similar molecules attracting 

 each other. There is no doubt of this ; and hence the 

 presumption that the similar molecules in the two 

 wires, and in the parts surrounding them, ought to 

 exercise reciprocal attraction ; for the whole burden of 

 the previous evidence has gone to show that there is 

 an intimate if not inseparable connexion between 

 chemical and electrical action. 



It is more difficult to explain why the wires should 

 recede from each other when their currents are in 

 contrary directions ; but the explanation will in all 

 probability be found in a similar process of reasoning. 

 When two different kinds of salts are mixed together 

 in solution, like crystallizes with like. Similar 

 molecules attract each other. But is this all ? Do 

 dissimilar molecules repel each other at the same 

 time that similar molecules attract each other ? If 

 they do, then it may be argued that the dissimilar 

 molecules of the the two wires and the surrounding 

 media, when currents are passed through the wires 

 in contrary directions, will repel each other, and this 



