RELATIONS TO OTHER SCIENCES 143 



This conception, this electronic theory of matter in which matter 

 becomes, at least partially, synonymous with electricity in motion, 

 appears to account for an enormous number of facts, which increase 

 constantly under the efforts of physicists impatient to contemplate 

 in a less primitive form the synthesis which it promises to bring 

 forward. 



(30) Stability of the Electron. The fundamental conception, that 

 of the electron, does not go without raising difficulties still further, 

 besides the impossibility already pointed out of representing to our- 

 selves by material images its displacement with respect to the ether. 

 It seems necessary to admit something else in its structure than its 

 electric charge, an action which maintains the unity of the electron 

 and prevents its charge from being dissipated by the mutual repul- 

 sions of the elements which constitute it. The form of the electron 

 is determined by some relation which insures its stability, the con- 

 dition of incompressibility of the medium being insufficient, since 

 the spherical form corresponds only to unstable equilibrium for an 

 electrified body of given volume in which no force opposes the deform- 

 ation. 



This condition, which belongs to some fundamental property of 

 the medium, determining the charge carried by the electrons, all 

 identical from this point of view, is perhaps closely connected with 

 the third mode of activity of the ether, a third form of energy, the 

 gravitational form, of which our principle of stationary energy ought 

 to take account by the addition of terms to those expressing the 

 electrostatic energy, but of infinitely smaller magnitude. 



(31) Gravitation. Gravitation remains obstinately outside of our 

 electromagnetic synthesis; the Newtonian forces not only do not 

 appear to be propagated with the velocity of light, but also it seems 

 difficult to found them on electromagnetism without modifying 

 profoundly our fundamental ideas in regard to field and quantity 

 of electricity and the possibility of an attraction of one aggregation of 

 neutral electrons for another aggregation of the same nature. 



It appears probable that gravitation results from a mode of activity 

 of the ether and a property of electrons entirely different from the 

 electromagnetic mode, and we must admit besides electric and mag- 

 netic energies, a third distinct form, that of gravitation. 



It remains to understand how it is possible, and what is the sig- 

 nificance of the equivalence, the passage of this third form into one 

 of the first two. Also we are no more capable of understanding, out- 

 side of the formal equations which express it, the connection 

 between the electric and magnetic energies themselves and their 

 transformations, the one into the other, by means of the electrons. 



(32) An Experiment Necessary. It does not seem impossible to 

 connect the forces of cohesion with electromagnetism, especially 



