PROGRESS OF ELECTRICAL THEORY. 39 



vitation itself becomes an electrical phenomenon, 

 arising from the residual excess of attraction over 

 repulsion ; and the fact which is urged against the 

 hypothesis becomes a confirmation of it. By this 

 consideration the prerogative of simplicity passes 

 over to the side of the hypothesis of one fluid ; and 

 the rival view appears to lose at least all its supe- 

 riority. 



Very recently, M. Mosotti 16 has calculated the 

 results of the JEpinian theory in a far more com- 

 plete manner than had previously been performed; 

 using Laplace's coefficients, as Poisson had done 

 for the Coulombian theory. He finds that, from the 

 supposition of a fluid and of particles of matter 

 exercising such forces as that theory assumes, (with 

 the very allowable additional supposition that the 

 particles are small compared with their distances,) 

 it follows that the particles would exert a force, 

 repulsive at the smallest distances, a little further 

 on vanishing, afterwards attractive, and at all sen- 

 sible distances attracting in proportion to the in- 

 verse square of the distance. Thus there would be 

 a position of stable equilibrium for the particles at 

 a very small distance from each other, which may 

 be, M. Mosotti suggests, that equilibrium on which 

 their physical structure depends. According to this 

 view, the resistance of bodies to compression and 

 to extension, as well as the phenomena of statical 



16 Sur les Forces qui regissent la Constitution Interieure des 

 Corps. Turin. 1836. 



