and
respectively. From the replacement of
by
he deduced that the number of electrons in the ring was equal to 4. This view, however, can hardly be maintained. The approximate agreement mentioned above with Whiddington’s measurements for the energy necessary to produce the characteristic radiation indicates very strongly that the spectrum is due to a displacement of a single electron, and not to a whole ring. In the latter case the energy should be several times larger. It is also pointed out by Nicholson[30] that Moseley’s explanation would imply the emission of several quanta at the same time; but this assumption is apparently not necessitated for the explanation of other phenomena. At present it seems impossible to obtain a detailed interpretation of Moseley’s results, but much light seems to be thrown on the whole problem by some recent interesting considerations by W. Kossel[31].
Kossel takes the view of the nucleus atom and assumes that the electrons are arranged in rings, the one outside the other. As in the present theory, it is assumed that any radiation emitted from the atom is due to a transition of the system between two steady states, and that the frequency of the radiation is determined by the relation (1). He considers now the radiation which results from the removal of an electron from one of the rings, assuming that the radiation is emitted when the atom settles down in its original state. The latter process may take place in different ways. The vacant place in the ring may be taken by an electron coming directly from outside the whole system, but it may also be taken by an electron jumping from one of the outer rings. In the latter case a vacant place will be left in that ring to be replaced in turn by another electron, etc. For the sake of brevity, we shall refer to the innermost ring as ring 1, the next one as ring 2, and so on. Kossel now assumes that the
radiation results from the removal of an electron from ring 1, and makes the interesting suggestion that the line denoted by Moseley as