248 SCIENCE AND METHOD. 



considerable production of heat, and, notwithstanding 

 that, a very appreciable resistance of the medium. 



If we suppress the corpuscles and return to the 

 hypothesis of the Maxwell-Bartholi pressure, the 

 difficulties are no smaller. It is this that tempted 

 Lorentz himself in his Memoire to the Academy of 

 Sciences of Amsterdam of the 25th of April 1900. 



Let us consider a system of electrons immersed in 

 an ether traversed in all directions by luminous waves. 

 One of these electrons struck by one of these waves 

 will be set in vibration. Its vibration will be syn- 

 chronous with that of the light, but there may be a 

 difference of phase, if the electron absorbs a part ot 

 the incident energy. If indeed it absorbs energy, it 

 means that it is the vibration of the ether that keeps 

 the electron in vibration, and the electron must ac- 

 cordingly be behind the ether. An electron in motion 

 may be likened to a convection current, therefore 

 every magnetic field, and particularly that due to the 

 luminous disturbance itself, must exercise a mechani- 

 cal action upon the electron. This action is very 

 slight, and more than that, it changes its sign in the 

 course of the period ; nevertheless the mean action 

 is not nil if there is a difference of phase between 

 the vibrations of the electron and those of the ether 

 The mean action is proportional to this difference, 

 and consequently to the energy absorbed by the 

 electron. 



I cannot here enter into the details of the calcula- 

 tions. I will merely state that the final result is an 

 attraction between any two electrons varying in the 

 inverse ratio of the square of the distance, and pro- 

 portional to the energ)- absorbed by the two electrons. 



