CHAPTER XII. 



THE LAW OF SUBSTANCE. 



The fundamental chemical law of the constancy of matter. The 

 fundamental physical law of the conservation of energy. 

 Combination of both laws in the law of substance. The 

 kinetic, pyknotic, and dualistic ideas of substance. Monism of 

 matter. Ponderable matter. Atoms and elements. Affinity of 

 the elements. The soul of the atom (feeling and inclination). 

 Existence and character of ether. Ether and ponderable matter. 

 Force and energy. Potential and actual force. Unity of natural 

 forces. Supremacy of the law of substance. 



The supreme and all-pervading law of nature, the 

 true and only cosmological law, is, in my opinion, 

 the law of substance ; its discovery and establishment 

 is the greatest intellectual triumph of the nineteenth 

 century, in the sense that all other known laws of 

 nature are subordinate to it. Under the name of 

 " law of substance " we embrace two supreme laws of 

 different origin and age — the older is the chemical 

 law of the " conservation of matter," and the younger 

 is the physical law of the " conservation of energy." 1 

 It will be self-evident to many readers, and it is 

 acknowledged by most of the scientific men of the 

 day, that these two great laws are essentially 

 inseparable. This fundamental thesis, however, is 

 still much contested in some quarters, and we must 



1 Cf. Monism, by E. Haeckel. 

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