corresponding to a field of 28500 and 74000 volts per cm. respectively. The third and fifth columns give the values of
where
should be a constant for all the lines and equal to unity.
| 28500 volts. per cm. | 74000 volts. per cm. | ||||
|---|---|---|---|---|---|
 |  |  |  | | |
| 2 | 3 | 0.46 | 0.83 |  | |
| 2 | 4 | 1.04 | 0.79 | 2.86 | 0.83 |
| 2 | 5 | 2.06 | 0.89 | 5.41 | 0.90 |
| 2 | 6 | 3.16 | 0.90 | 7.81 | 0.85 |
| 2 | 7 | 4.47 | 0.90 | | |
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 considered 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 corresponding 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 intensities; when the spectrum is produced by positive rays, it was found that the component of highest frequency is the stronger if the rays travel against the electric field, while if it travels in the direction of the field the component of smallest frequency is the stronger (loc. cit. p. 40). This indicates that the components are produced independently of each other—a result to be expected if they correspond to quite different orbits of the electron. That the orbit of the electron in general need not be circular is also very strongly indicated by the observation that the hydrogen lines emitted from positive rays under certain conditions are partly polarized without the presence of a strong external field (loc. cit. p. 12). This polarization, as well as the observed intensity differences of the two components, would be explained if we can assume that for some reason, when the atom is in rapid motion, there is a greater probability for the orbit of the electron to lie behind the nucleus rather than in front of it.