THE NEW THEORY OF MATTER. 499 



ous. But whether this final unification be accepted or not, it is cer- 

 tain that these monads can not be considered apart from the ether. It 

 is on their interaction with the ether that their qualities depend — and 

 without the ether an electric theory of matter is impossible. 



Surely we have here a very extraordinary revolution. Two cen- 

 turies ago electricity seemed but a scientific toy. It is now thought by 

 many to constitute the reality of which matter is but the sensible ex- 

 pression. It is but a century ago that the title of an ether to a place 

 among the constituents of the universe was authentically established. 

 It seems possible now that it may be the stuff out of which that uni- 

 verse is wholly built. Nor are the collateral inferences associated with 

 this view of the physical world less surprising. It used, for example, 

 to be thought that mass was an original property of matter: neither 

 capable of explanation nor requiring it; in its nature essentially un- 

 changeable, suffering neither augmentation nor diminution under the 

 stress of any forces to which it could be subjected ; unalterably attached 

 to, or identified with, each material fragment, howsoever much that 

 fragment might vary in its appearance, its bulk, its chemical, or its 

 physical condition. 



But if the new theories be accepted these views must be revised. 

 Mass is not only explicable, it is actually explained. So far from 

 being an attribute of matter considered in itself, it is due, as I have 

 said, to the relation between the electrical monads of which matter is 

 composed and the ether in which they are bathed. So far from being 

 unchangeable, it changes, when moving at very high speeds, with every 

 change in its velocity. 



Perhaps, however, the most impressive alteration in our picture of 

 the universe required by these new theories is to be sought in a differ- 

 ent direction. We have all, I suppose, been interested in the generally 

 accepted views as to the origin and development of suns with their 

 dependent planetary systems; and the gradual dissipation of the en- 

 ergy which during this process of concentration has largely taken the 

 form of light and radiant heat. Follow out the theory to its obvious 

 conclusions, and it becomes plain that the stars now visibly incandes- 

 cent are those in^ mid-journey between the nebulas from which they 

 sprang and the frozen darkness to which they are predestined. What, 

 then, are we to think of the invisible multitude of the heavenly bodies 

 in which this process has been already completed? According to the 

 ordinary view, we should suppose them to be in a state where all pos- 

 sibilities of internal movement were exhausted. At the temperature 

 of interstellar space their constituent elements would be solid and in- 

 ert; chemical action and molecular movement would be alike impos- 

 sible, and their exhausted energy could obtain no replenishment unless 

 they were suddenly rejuvenated by some celestial collision, or traveled 

 into other regions warmed by newer suns. 



