CONTENT 



Introduction :\ (287 1 



Part I. 



Examination of the trigonometric series representing the motion of the electron 

 in the hydrogen atom. 



§ 1. General metliod applicable to conditionally periodic systems .'> ('289} 



§ 2. Hydrogen atom undisturbed by external influences 1(1 (i94) 



§ 3. Hydrogen atom under tlie influence of a strong homogeneous electric field of force 16 (300| 



§ 4, Hj'drogen atom under tlie influence of a weak homogeneous electric field of force 20 (310) 



Pari II. 



Discussion of the intensities of the components of the hydrogen lines. 



§ ."). Application of the quantum theory to the problem of the intensity of spectral lines . . 38 (322) 



S 6. The Stark effect of the hydrogen lines 49 (333) 



§ 7. The fine structure of the hydrogen lines 68 (3.Ï2) 



1. The relative intensities of the components of the fine structure of the lines of the 



spectrum of the undisturbed hydrogen atom 71 (355) 



II. Effect of a weak electric field on the fine structure 75 (359) 



III Comparison of the theorj' with the observations on the fine structure 84 (368) 



S 8. The effect of a magnetic field on the fine structure of the hydrogen lines. 94 (378) 



