404 



Dr. N. Bohr on the Quantum Theory of 



in the Balmer series*. The first column gives the values for 

 the numbers n Y and n 2 . The second and fourth columns give 

 the frequency difference Au corresponding to a field of 28500 

 and 74000 volts per cm. respectively. The third and fifth 



columns give the values of 



a = Av 



4tt 2 < 



t mh(n 2 2 -n 1 2 )' 



where u should be a constant for all the lines and equal to 

 unity. 



n l 



n. 2 



28500 volts 



. per cm. 



74000 volts 



per cm. 



kv . 10~ 12 

 046 



Av.10" 12 



a 



•2 



3 



83 







2 



4 



104 



0-79 



2-86 



0-83 



2 



5 



2-06 



0-89 



5-41 



090 



2 



6 



3-16 



0-90 



7-81 



0-85 



2 



7 



4-47 



090 







Considering the difficulties of accurate measurement of the 

 quantities involved, it will be seen that the agreement with 

 regard to the variation of the frequency differences from line 

 to line is very good. The fact that all the observed values 

 are a little smaller than the calculated may be due to a slight 

 over-estimate of the intensity of the fields used in the 

 experiments (see Stark, loc. cit. pp. 38 and 118). Besides 

 the two strong outer components polarized parallel to the 

 field, Stark's experiments have revealed a large number of 

 inner weaker components polarized in the same way, and also 

 a number of components polarized perpendicular to the field. 

 This complexity of the phenomenon, however, cannot be con- 

 sidered as inconsistent with the theory. The above simple 

 calculations deal only with the two extreme cases, and we 

 may expect to find a number of stationary states correspond- 

 ing to orbits of smaller excentricity. In a discussion of such 

 non-periodic orbits, however, the general principles applied 

 are no longer sufficient guidance. 



Apart from the agreement with the calculations, Stark's 

 experiments seem to give strong support to the interpretation 

 of the origin of the two outer components. It was found 

 that the two outer components have not always equal inten- 

 sities ; when the spectrum is produced by positive rays, it 

 * Stark, loc. cit. pp. 51, 54, 55, & 56. 



