Theories of Electricity 153 



I must now reluctantly face the question which I have 

 put off as long as possible: "What is positive electric- 

 ity?" for here I recognize that I must tread with cau- 

 tion. Science to-day has arrived at a fairly clear con- 

 ception of negative electricity, but with regard to posi- 

 tive, it is unable to speak with the same definiteness. If 

 we have a negative electron as a carrier of negative elec- 

 tricity, it might reasonably be expected that there should 

 exist a corresponding positive electron. An examina- 

 tion of the carriers of positive electricity in a vacuum 

 tube has, however, disclosed the fact that positive elec- 

 tricity is always found associated with bodies atomic in 

 size, which have several thousand times the mass of the 

 negative carrier or electron. Even in radium and the 

 other radioactive bodies, in which the electrical proc- 

 esses appear to be extremely fundamental in character, 

 the CL particle or carrier of the positive charge has a 

 mass about that of the atom of the rare gas helium. We 

 have no evidence at all that a positive electron of mass 

 small compared with the atom exists. A positively 

 charged ion is now regarded as an atom or molecule 

 which has lost one of its constituent electrons, but this 

 method of expression, in a sense, begs the fundamental 

 question of the true character of positive electricity. 



In order to answer this question, it is probable that 

 we must know the exact connection which exists between 

 positive and negative electricity and the medium or 



