I 3 2 THE LIMITATIONS OF SCIENCE 



such name as protion. This unit of matter must be 

 reduced in size as refinement of observation increases, 

 so that we may always be able to discuss it mathe- 

 matically in the aggregate only. It must also be en- 

 dowed with the same attributes which we recognize in 

 gross matter. 



At the present time this protion is the electron, and 

 the only attributes necessary to assign to it are inertia 

 in the Newtonian sense, a force of gravitational attrac- 

 tion and a force of electrical attraction, either positive 

 or negative in sign. No causes for these attributes 

 can be given, as they are fundamental. If the experi- 

 ments of Kaufmann, which show that an electrified 

 particle in motion has an apparently increased mo- 

 mentum, are cited as supporting the view that inertia 

 is a function of velocity and should be considered as 

 an attribute of an invariable quantity, the electrical 

 charge, I hope to show that it is possible to accept 

 Kaufmann's results and at the same time the invari- 

 ability of inertia. Before proceeding further with this 

 discussion it is convenient to assemble the foregoing 

 ideas in a more concise form. 



We have first postulated a real and objective uni- 

 verse and assigned to matter rather than to energy the 

 role of being an entity. The fundamental attribute of 

 matter which makes it recognizable by our senses is 

 force. 



We next assumed that quantitatively all phenomena 



