THE THREE ENTITIES. 5 



insists that these waves shall inhere in something. The 

 ocean waves s^re made of water, sound waves of air, 

 light waves of, we must say, something. This something 

 cannot be air or waterxpr any form of matter as we know it, 

 for throughout that great reach of 93,000,000 of miles be- 

 tween the sun and us there exists but empty space. Filled 

 this empty space is, however, and to the brim. There is no 

 such thing as emptiness. From corner to corner of the 

 universe, wherever a star shines or light darts, there broods 

 this vast circumambient medium the ether. Not only 

 through interstellar spaces, but through the world also, in 

 all its manifold complexity, through our own bodies; all lie 

 not only encompassed by it but soaking in it as a sponge 

 lies soaked in water. How much we ourselves are matter 

 and how much ether is, in these days, a very moot question. 



ENERGY. 



Just as there is no such thing as emptiness, so there is 

 no such thing as rest. It is doubtful that there is such a 

 thing as rest even in a relative sense. The very particles 

 that constitute the materials of our so-solid-seeming earth, 

 that seem so fixed and at rest relatively to one another are 

 in a state of perpetual unremitting quiver what we call 

 temperature and that quivering, had we eyes but big 

 enough to see it, is very far, indeed, removed from rest. 

 Now, this motion is continually changing, from one velocity 

 to another, and the same kind of reasoning that led us to 

 believe in the ether leads us to believe that a body can go 

 faster or slower only because of some cause. This cause, 

 or this power to change the state of motion of a body, is 

 energy. 



Just as matter may exist in so many different forms, so 

 may energy, a list of the forms of which we append: 



