TWO THEORIES OF KNOWLEDGE 69 



to explain has received a notable confirmation from 

 the establishment during the latter part of the nine- 

 teenth century of the scientific doctrine of Energy. 1 

 The culmination of the scientific fabric of which 

 Galileo and Newton laid the foundations was 

 reached when it was demonstrated that the whole 

 physical universe must be regarded as composed 

 of Energy, either kinetic and actually undergoing 

 transmutation from one form to another, or 

 potential and quiescent yet containing within 

 itself the quantifiable capacity of transformation. 

 The objective correlatives of the different classes of 

 sensible experiences are found to be different forms 

 which this Energy assumes the kinetic energy of 

 a mass in motion, the radiant energy of Light, 

 the energy of Heat, the potential energy of chemical 

 separation, etc. all these have now at length been 

 shown to be forms of one real thing capable under 

 / appropriate conditions of being transmuted into 

 each other and of which not only the inter- 

 transmutability but the equivalent values can 

 be calculated and have been found by experi- 

 ment to be fixed and definite. Thus the 

 mechanical equivalent of heat is a fixed and 



1 For a clear brief summary of the theory the reader may be 

 referred to a little work by Sir William Ramsay, F.R.S., entitled 

 Elements and Electrons, pp. 8-16. 



