6 THE NEW KNOWLEDGE. 



1. KINETIC ENERGY. 6. CHEMICAL ENERGY. 



2. GRAVITATION ENERGY. 7. ELECTRICAL ENERGY. 



3. HEAT. 8. MAGNETIC ENERGY. 



4. ENERGY OF ELASTICITY. 9. RADIANT ENERGY. 



5. COHESION ENERGY. 



This list comprises " forms" of energy and not " differ- 

 ent energies/' for the reason that they are one and all inter- 

 convertible. Energy is protean in its nature for it may be 

 converted, directly or indirectly, into any other form. They 

 are, therefore, different phases of one thing, not different 

 things. For example, the energy of the burning coal is 

 converted consecutively into heat, into mechanical energy, 

 into electrical energy, and, finally, in some far away street, 

 into the radiant energy of the arc lamp. It is possible, 

 even, that these very " forms" may not be distinct from 

 one another, actually, but are simply so many different 

 varieties of motion^, o F 



However that may be, energy is not only transformable 

 but transferable. In a word, we may transfer energy from 

 one body to another indefinitely. We may load the energy 

 from a waterfall into a dynamo and from the dynamo into a 

 sewing machine. Matter is but a stepping-stone to energy, 

 here and away, through one form to another and from one 

 body to another, infinitely restless, constant only to one 

 thing, its total quantity. However much energy may be 

 transformed or transferred, when any quantity of one form 

 disappears, a precisely equal quantity simultaneously ap- 

 pears in some other form or forms. Just as with matter, 

 you cannot create or destroy any quantity of energy how- 

 ever small, and since energy is the great worker of the 

 universe you cannot get something for nothing. No ma- 

 chine can make energy, and it is curious that this fact is 



