146 
Proceedinors of the Royal Society of Edinburgh. [Sess. 
already in the atom is the converse process. It is associated with an 
angular impulse in the atom from which it is emitted. 
Hence, for the reasons indicated in this note, the emission of an electron 
is associated with angular oscillations — that is to say, with radiation ; from 
which it may be inferred that the theory has a bearing on the phenomena 
of photo-electricity. We may imagine the magnetic system of the atom to 
be thrown into oscillation by resonance as a result of the incidence of 
light of appropriate wave-length, and when the amplitude reaches a 
certain limit an electron is ejected. In being ejected it exerts an angular 
impulse which stops the oscillation and deprives the atom of the quantum 
of energy which it has absorbed through resonance. 
{Issued separately June 6 , 1922 .) 
