22 HISTORY OF ELECTRICITY. 



was not at once, or at least, not generally adopted. 

 The hypothesis of the excess and defect of a single 

 fluid is capable of being so treated as to give the 

 same results with the hypothesis of two opposite 

 fluids, and happened to obtain the preference for 

 some time. We have already seen that this hypo- 

 thesis, according to which electric phenomena arose 

 from the excess and defect of a generally diffused 

 fluid, suggested itself to Watson and Franklin 

 about 1747. Watson found that when an electric 

 body was excited, the electricity was not created, 

 but collected ; and Franklin held, that when the 

 Ley den jar was charged, the quantity of electricity 

 was unaltered, though its distribution was changed. 

 Symmer 2 maintained the existence of two fluids ; 

 and Cigna supplied the main defect which belonged 

 to this tenet in the way in which Dufay held it, 

 by showing that the two opposite electricities were 

 usually produced at the same time. Still the ap- 

 parent simplicity of the hypothesis of one fluid 

 procured it many supporters. It was that which 

 Franklin adopted, in his explanation of the Leyden 

 experiment ; and though, after the first conception of 

 an electrical charge as a disturbance of equilibrium, 

 there was nothing in the developement or details 

 of Franklin's views which deserved to win for them 

 any peculiar authority, his reputation, and his skill 

 as a writer, gave a considerable influence to his 

 opinions. Indeed, for a time he was considered, 



' 2 Phil. Trans. 1759. 



