CHAPTER II 



THE SUBSTANCE OF NATURE 



24. Matter. Diverse and innumerable as the things 

 around us seem to be, the number of kinds is reduced greatly 

 when they are tested by trying to destroy them. Only what 

 cannot be annihilated is real, according to our definition 

 ( 5). Tested thus, air, wood, marble, vinegar, to take a 

 few random examples, appear unreal, for they can be 

 produced and destroyed. Closer study shows that though 

 burning destroys both wood and air it produces at the same 

 time other things ashes, water, carbonic acid, nitrogen 

 exactly equal in amount though different in properties. 

 Vinegar and marble are both destroyed by mixing them, 

 but other things calcium acetate, carbonic acid, water 

 appear in exactly the same amount. So with all the things 

 we see or feel, their properties and appearance can be 

 completely changed, but the amount of substance that 

 exists in them cannot be increased or diminished by any 

 power which man has learned to wield. Substance is thus 

 a real thing, of which air, wood, marble, Vinegar and the 

 rest are kinds. The term Matter is applied to every- 

 thing, however diverse in appearance, which we see and 

 touch, as Man is the term used to include every human 

 being in the world. The difference between some kinds 

 of matter is as slight and superficial as that between soldiers 

 and chimney-sweeps ; between other kinds it may be com- 

 pared to that which separates Europeans from Negroes. 



25. Energy. There is another real thing which does 



