140 THE LIMITATIONS OF SCIENCE 



electrical charges, might deposit different amounts of 

 matter if it were sufficient in quantity to be detected by 

 chemical or mechanical reactions. 



As an hypothesis, I propose that, in order to make 

 the ratio ^ agree with the experimental evidence of its 

 value and to account for electro-magnetic mass, we 

 consider m to be the mass of a particle of matter in 

 the Newtonian sense, of constant and small value, and 

 e, the electrical charge, to be a force attribute of mat- 

 ter which varies with the velocity of the particle. 



However novel this hypothesis may be, I have not 

 been able to find any experimental facts more difficult 

 to explain by it than by any of the other hypotheses 

 which have been recently advanced ; and, on the other 

 hand, it apparently accounts for much of the modern 

 work in terms of old and well-established ideas. 



From the very nature of my conception of the limits 

 which should be imposed on scientific inquiry, I make 

 no attempt to explain the cause for this electrical prop- 

 erty of matter any more than I should for its gravita- 

 tional attributes. Both are fundamental phenomena to 

 be accepted as experimental facts until we gain con- 

 trary knowledge. Indeed, I have ventured to indulge 

 in this speculation rather with the idea of showing 

 that the recent hypotheses for electricity and matter; 

 for the ether, protions, and corpuscular light ; for the 

 electro-magnetic and other non-Newtonian mechanics, 

 are not necessary. We may still account as adequately 



