Continuity 61 



ics, with mass and shape a function of 

 velocity, is an immediate consequence of 

 the electrical theory of matter. The de- 

 pendence of inertia and shape on speed 

 is a genuine discovery and, I believe, 

 a physical fact. The Principle of Rela- 

 tivity would reduce it to a conventional 

 fiction. It would seek to replace this real 

 change in matter by imaginary changes in 

 time. But surely we must admit that 

 Space and Time are essentially unchange- 

 able: they are not at the disposal even of 

 mathematicians; though it is true that 

 Pope Gregory, or a Daylight-saving Bill, 

 can play with our units, can turn the ^d 

 of October in any one year into the I4th, 

 or can make the sun South sometimes at 

 eleven o'clock, sometimes at twelve. 1 



But the changes of dimension and mass 

 due to velocity are not conventions but 



1 In the historical case of governmental interference with 

 the calendar, no wonder the populace rebelled. Surely 

 some one might have explained to the authorities that 

 dropping leap-year for the greater part of a century would 

 do all that was wanted, and that the horrible inconven- 

 ience of upsetting all engagements and shortening a single 

 year by eleven days could be avoided. 



