PROGRESS OF ELECTRICAL THEORY. 35 



yEpinus 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 general as 

 might have been reasonably expected from its very 

 beautiful accordance with the facts which it contem- 

 plates. 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 

 experimenters and writers of works of general cir- 

 culation. The theory of jEpinus was explained by 

 Robison in the Encyclopaedia Britannica ; the ana- 

 lysis of Poisson has recently been presented to the 

 public in the Encyclopaedia Metropolitan^ but is of 

 a kind not easily mastered even by most mathema- 

 ticians. 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 mea- 

 sured experiments. Mr. Snow Harris 



