136 ELEMENTS OF SCIENCE 



unimaginable form of energy which manifests itself 

 according to circumstances as heat, light, electricity, 

 magnetism and chemical energy ; or else that there are 

 fundamentally different forms of force which have be- 

 tween them relations of quantitative equivalence as they 

 act. The former is the view now popular. These, how- 

 ever, are questions so remote from the mere elements 

 of science, that we will no further deal with them here, 

 but proceed to consider that real world wherein all these 

 physical energies play their several parts. 



