Radiation and the Structure of the Atom. 413 



should be several times larger. It is also pointed out by 

 Nicholson * 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 f. 



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 stntes, and that the frequency of 

 the radiation is determined by the relation (1). He con- 

 siders now the radiation which results from the removal of 

 an electron from one of the rings, assuming that the radia- 

 tion 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 K radiation results from the removal of an 

 electron from ring 1, and makes the interesting suggestion 

 that the line denoted by Moseley as K a corresponds to the 

 radiation emitted when an electron jumps from ring 2 to 

 ring 1, and that the line Kp corresponds to a jump from ring 3 

 to ring 1. On this view, we should expect that the K radiation 

 consists of as many lines as there are rings in the atom, the 

 lines forming a series of rapidly increasing intensities. For 

 the L radiation, Kossel makes assumptions analogous to 

 those for the K radiation, with the distinction that the 

 radiation is ascribed to the removal of an electron from 

 ring 2 instead of ring 1. A possible M radiation is ascribed 

 to ring 3, and so on. The interest of these considerations is 

 that they lead to the prediction of some simple relations 

 between the frequencies v of the different lines. Thus it 

 follows as an immediate consequence of the assumption used 

 that we must have 



K y Kq l^ L a M a 



* Nicholson, Phil. Mag. xxvii. p. 562 (1014). 



+ Kossel, Verh. d. Deutsch. Phys. Ges. xvi. p. 953 (1914). 



