CHAPTER III. 

 THE NATURE OF ELECTRICITY. 



THE CONSERVATION OF ENERGY. A clear under- 

 standing of that great doctrine of modern science, 

 known as the conservation of energy, lies at the founda- 

 tion of a correct knowledge of electricity and electric 

 phenomena. Hence a brief examination of its prin- 

 ciples will not be out of place here. 



Energy is a universal property of matter. It is the 

 principle of life and movement in matter in distinc- 

 tion from matter itself, inseparably connected with 

 matter and yet distinct from it : heat as distinct from 

 the heated body ; electricity as distinct from the elec- 

 trified body ; life as distinct from the living body. 



Like matter, it manifests itself in various forms, 

 as gravity, cohesion, chemical affinity, light, heat, elec- 

 tricity. Like matter, its quantity in the universe is 

 fixed and definite, and cannot be increased or dimin- 

 ished. And hence, like matter, it is indestructible. 



It may be transmuted from one form into another, 

 but in the transmutation there is no loss. One form 

 may re-appear in many forms, or the many be reduced 

 to the one. 



In our experiments, muscular energy has been ex- 

 pended to produce electric energy ; but the energy pro- 

 duced must equal that which produced it, if the doc- 

 trine of the conservation of energy is true. And since 



