282 FARM MOTORS 



Potential : 



1. Fuel. 



2. Food. 



3. Head of water. 



4. Chemical forces. 



Kinetic or actual : 



1. Air in motion, or the wind. 



2. The waterfall. 



3. Tides. 



The energy found in the forms just mentioned must 

 be converted into a form in which it may be applied to 

 machines for doing work. This change of the energy 

 from one form to another is spoken of as the transforma- 

 tion of energy. 



The law of transformation of energy holds that when a 

 definite amount of energy disappears from one form a 

 definite amount appears in the new form, or there is a 

 quantivalence. 



Prime movers are those machines which receive energy 

 directly from natural sources and transmit it to other 

 machines which are fitted for doing the various kinds of 

 useful work. 



398. Forms of motors: 



1. The animal body. 



2. Heat engines 



Air, 



Gas or vapor, 



Steam, 



Solar. 



3. Water wheels. 



4. Tidal machines. 



5. Windmills. 



6. Electrical motors. 



Of the above all are prime movers except the last 

 named, the electrical motors, The energy for the animal 



