Theories of Electricity 155 



ically investigated the properties of model atoms con- 

 sisting of a large number of rapidly revolving electrons 

 held in equilibrium by their mutual repulsions and the 

 forces due to a fixed and immobile distribution of pos- 

 itive electricity. He has shown that such electronic sys- 

 tems imitate in a striking way many of the most funda- 

 mental properties of the chemical atom. 



We must here, however, content ourselves with only 

 a passing reference to these brilliant attempts to discover 

 the character of atomic structure. 



We thus see that, on modern views, positive electricity 

 plays a very minor role in electrical effects, compared 

 with the omnipresent electron. The electrons are the 

 bricks of the atomic structure, while positive electricity 

 plays the humble but important part of the mortar to 

 bind them together. Such a division of respective roles 

 may appear somewhat arbitrary, but it suffices for the 

 present as the simplest method of explaining the experi- 

 mental facts. 



After a century and a half of great scientific activity, 

 which has added enormously to our knowledge of elec- 

 tricity, the ideas of electricity, which are in vogue to-day 

 bear a remarkable resemblance to those advocated by 

 Franklin in the infancy of the subject. This resem- 

 blance must have been obvious to you all in the light of 

 the recent developments which have been touched upon 

 in this paper. We believe that there is one kind of elec- 



