190 THE WORLD-ENERGY 



while the two "kinds" of electricity are seen to be but 

 two phases or degrees of one and the same kind. 



But we have further to note that all strains pro- 

 ducing flexure or compression in short, any change 

 whatever, whether "mechanical" or " chemical,," in 

 the configuration, or volume, or state, of any given 

 mass of matter must be attended with a greater or 

 less degree of molecular friction, resulting in "elec- 

 trification," as well as in change of temperature. In 

 short, electricity is evidently a phase of all matter, 

 and a phase no less essential than is heat or gravita- 

 tion. 



At the same time, it must not be overlooked that 

 in still another way the complexity of electric energy 

 is evident. For in its manifestations there are ever 

 found to be two phases possessing opposite character- 

 istics, and to which are given the designations respect- 

 ively of "positive" and "negative." It is to be 

 observed, however, that the law which these mani- 

 festations are found to follow brings out a peculiar 

 result. The law is that "like electricities repel and 

 unlike electricities attract." But this can, in reality, 

 mean nothing else than that positive electricity is 

 negative toward positive, and positive toward negative 

 electricity ; while negative electricity is positive toward 

 positive, and negative toward negative. 



And not only so, but the designation of the one 

 rather than the other as positive is found to be 

 purely arbitrary. Either is equally positive and equally 

 negative. Each is therefore both positive and negative. 



This is a specially significant phase of relation in 

 force, to which we shall have occasion to return. 



