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VI. An Electromagnetic Theory of Radiation. 

 By H. Bateman *. 



1. QOME interesting suggestions with regard to the nature 

 k3 of radiation have been made recently by Sir Joseph 

 Thomson t and Leigh Page %. According to the first writer, 

 radiation of energy seems to be generally associated with the 

 formation of closed lines of electric force which travel away 

 from a source with the velocity of light. In Page's work 

 radiation of energy is supposed to be caused by a rotation of 

 the field of an electron, and it folio w r s from his expressions 

 for the field vectors in a rotating field that this field may be 

 obtained by superposing on the non-rotating field of an elec- 

 tron a radiant field in which circular lines of electric force 

 travel outwards with the velocity of light. 



Paoe's work is particularlv interesting because the amount 

 of energy radiated in one complete revolution of the field is 

 almost exactly ifehv, where v is the frequency of the rotation 

 and Ji is Planck's constant. In order that v may be identified 

 with the frequency of the emitted light, it seems necessary 

 either to assume the existence of discrete tubes of force or 

 to extend Page's analysis to the case in which an electron 

 revolves or oscillates with its frequency of rotation. 



A peculiar feature of the radiant field is that there is a 

 radiation of magnetic charges which travel along straight 

 lines with the velocity of light §. There is, however, no 

 magnetic charge associated with the electron, and so it seems 

 likely that the magnetic charges arise from a distribution of 

 magnetic doublets which in turn arise from moving electric 

 doublets. Whether this is the case or not, the mathematical 

 analysis suitable for the formal development of this theory 

 of radiation is akin to that which has been given in the 

 present author's speculations regarding the electrical nature 



* Communicated by the Author. 



t ' Engineering,' vol. 101. p. 381 (1916) ; Phil. Mag. June 1920, p. 079. 



X Proc. Nat. Acad. Sci. March 1920, p. 115. 



§ A class of radiant tields in which there is a radiation of magnetic 

 particles in particular directions was found by the present author. Proc. 

 Nat. Acad. iSci. March 1918. It is probable" that Page's radiant field 

 can be built up by superposing a number of fields of this older type. It 

 may be remarked, too. that circular lines of electric force can bo obtained 

 in fields of the older type, and in this case it is possible for magnetic 

 charges which are equal but of opposite sign to be emitted in consecutive 

 directions. Circular lines of electric force of opposite senses are then 

 generated in approximately the same region like vortices having different 

 senses of rotation. 



