the major axis of the orbit, and the two signs correspond to orbits in which the direction of the major axis from the nucleus is the same or opposite to that of the electric force respectively. Using the formulæ (4) and (5) and neglecting the mass of the electron compared with that of the nucleus, we get, therefore, for the energy of the system in the two states
respectively. This expression is the same as that deduced in paper IV. by an application of (6) to the expressions for the energy and frequency of the system. Applying the relation (1) and using the same arguments as in paper IV. p. 10, we are therefore led to expect that the hydrogen spectrum in an electric field will contain two components polarized parallel to the field and of a frequency given by
The table below contains Stark’s recent measurements of the frequency difference between the two strong outer components polarized parallel to the field for the five first lines in the Balmer series[17]. The first column gives the values for the numbers
and
. The second and fourth columns give the frequency difference