MACHINES 



71 



and pulleys. The eccentric controls the exhaust of the 

 used steam. 



The Steam Turbine. This is a form of the steam 

 engine which converts the energy of steam into mechanical 

 energy in much the same way 

 that the water turbine converts 

 the energy of falling water into 

 mechanical energy (Figure 68). 

 Steam is directed by nozzles 

 against the blades of the turbine 

 wheel, which is caused to revolve 

 at a very high rate of speed . The 

 steam can be used several times 

 by arranging the turbines in 

 series. Such engines are used on 

 the great ocean liners and where FlG - 68 - The Principle of the 



, -11 Steam Turbine. 



tremendous power is needed. 



Gasoline Engines. --The force in the gasoline engine 

 is that of expanding gases formed by the explosion of 

 gasoline vapor and air. 



A Gasoline Engine. 



