1078 
D, is excluded. It is however not easy to do so for the motion D, 
alone. We could prescribe for the centre of mass of the electrons 
an elliptical path of the form belonging to D,, but by this we 
should loose the homogeneousness of the equations for the free 
vibrations and the possibility of superposing them on the forced 
vibrations. 
It is easily seen, however, what form the dispersion formula for 
hydrégen will take if the motion of the centre of mass of the 
electrons is limited to the axis of the molecule. We may as well 
exclude al! disturbances in the plane of the path, as there is no 
electric moment in the case of the motions C, and C,. The only 
moment of the molecule is now in the Z-direetion and a calculation 
similar to that of Draijer shows that in his dispersion formula only 
the second term remains, so that 
n?—1 BG 2,153 
4nN — mw? 1 Sen OG 
are 
or 
2a Ne? 
De le 
s? 
~ ( 2,153 + 6,954 — 
mo” wo 
while the observations of Kocn give 
nl 1,361 10m4 2,908, 10m 2" s*. 
From this we obtain: 
DO = 5-00 On 
and using the value Ne = 1,289.10" 
2 
~ = 1,18. 10" 
m 
which is just twice what is found for the cathode rays. If the charge 
of a hydrogen atom were twice that of the particles in the cathode 
rays or if its mass were half that of these latter corpuscles RypBER@’s 
constant as calculated by Bonr from his analogous hypothesis 
concerning the hydrogen atom would no longer have the value that 
follows from the experiments *). 
Let us further consider the moment of momentum of each of the 
electrons. From the formula for this moment 
mw = zh 
and from that for the uniform rotation 
1) N. Bour. On the constitution of atoms and molecules [ Phil. Mag. 6: 26, 
1913 spa’: 
