m 



in 



Conservation of Matter 31 



each other, so as to encroach on each other's 

 agnetic field as they move, that then their 

 inertia may fall in value during the time 

 they are contiguous. No experimental fact 

 has yet suggested this at present : it is 

 improbable that even in the tightest com- 

 binations they ever really approach close 

 enough to each other to make the effect 

 appreciable in the slightest degree ; still, 

 strictly speaking, the inertia of matter is a 

 known mathematical function of the distance 

 of electrons apart, compared with their size, 

 as well as of their absolute speed through 

 the ether ; and hence it may be found to 

 vary from either of two distinct reasons. 

 Nevertheless, even this variation would not 

 be expressed as a failure in the conserva- 

 tion of matter^ though there is now 

 no single material property that can be 

 specified as really and genuinely constant. 

 So long as the electric centres of strain, 

 or whatever they are so long as the 

 electric charges themselves continue un- 

 altered, we should prefer to say that at 



