321 



electric field exerts on the electron. In the paper mentioned in the i)eginning ol 

 this section where the general problem, in which the perturbations due to the 

 electric force are not small compared to those due to the relativity modifications, 

 will be treated, it will be possible to elucidate the meaning and importance of the 

 simple character of the perturbations in the two special cases just described from a 

 general point of view. 



