PEOGEESS OF ELECTRICAL THEOEY. 200 



American and a politician ; for lie was already, in 1736, engaged in 

 public affairs as clert to the General Assembly of Pennsylvania, though 

 it was not -till a later period of his life that his admirers had the occa- 

 sion of saying of him 



Eripuit ccelis fulmen sceptrmnque tyrannis ; 



Born to control all lawless force,- all fierce and baleful sway, 

 The thunder's bolt, the tyrant's rod, alike he wrenched awuy. 



^Epinus. and Coulomb were two of the most eminent physical philo- 

 sophers of the last century, and labored in the way peculiarly required 

 by that generation ; whose office it was to examine the results, in par- 

 ticular subjects, of the general conception of attraction and repulsion, 

 as introduced by Newton. The reasonings of the Newtonian period 

 had, in some measure, anticipated all possible theories resembling the 

 electrical doctrine of JEpinus and Coulomb ; and, on that account, 

 this doctrine could not be introduced and confirmed in a sudden and 

 striking manner, so as to make a great epoch. Accordingly, Dufay, 

 Symmer, "Watson, Franklin, ^Epinus and Coulomb, have all a share in 

 the process of induction. "With reference to these founders of the 

 theory of electricity, Poisson holds the same place which Laplace holds 

 with reference to Newton. 



The reception of the Coulombian theory (so we must call it, for the 

 ^Epinian theory implies one fluid only,) has hitherto not been so gene- 

 ral as might have been reasonably expected from its very beautiful 

 accordance with the facts which it contemplates. This has partly been 

 owing to the extreme abstruseness of the mathematical reasoning 

 which it employs, and which put it out of the reach of most experi- 

 menters and writers of works of general circulation. The theory of 

 . Epinus was explained by Piobison in the Encyclopaedia Britannka ; 

 the analysis of Poisson has recently been presented to the public in 

 the Encyclopaedia Metropolitana, but is of a kind not easily mastered 

 even by most mathematicians. On these accounts probably it is, that 

 in English compilations of science, we find, even to this day, the two 

 theories of one and of two fluids stated as if they were nearly on a par 

 in respect of their experimental evidence. Still we may say that the 

 Coulombian theory is probably assented to by all who have examined 

 it, at least as giving the laws of phenomena ; and I have not heard of 

 any denial of it from such a quarter, or of any attempt to show it to be 

 erroneous by 'detailed and -measured experiments. Mr. Snow Harris 

 VOL. II 14. 



