134 THE LIMITATIONS OF SCIENCE 



radiant energy and, in order to link it with kinetic 

 energy, its quantity is expressed as the product of a 

 " mass " and a " velocity " factor. Its velocity is 

 naturally taken to be the distance between the bodies di- 

 vided by the observed time. It is most conveniently 

 expressed as a periodic motion with a translational 

 velocity equal to 3 x io 10 centimeters per second. No 

 hypothesis is made in regard to the nature of the mass 

 factor; it is taken merely as a coefficient to maintain 

 conservation. 



As no attempt is made to account for the mechanism 

 of radiation, no attributes need be assigned to an ether. 

 In fact no ether need be postulated, although it is 

 advisable to use the name to differentiate space when it 

 is occupied by radiant energy. 



Action at a distance is a matter of experience and 

 cannot be denied until some reasonable proof is found 

 to account for force by some other means. 



So far these ideas have had the approval of some 

 acute men of science, however they may be disapproved 

 of by others. Those which follow are more novel and 

 need to be supported. 



Since mechanical explanations are to be avoided, it is 

 necessary to endow the electron with all the attributes 

 of gross matter. For example, the protion of oxygen 

 has a different density, force of cohesion, etc., from 

 that of hydrogen. In this discussion, it is necessary 

 to discuss only a few of these attributes. 



