422 FARM MOTORS 



315). One connection should be from the lowest part of 

 the water jacket to the lower part of the tank ; the other 

 should be from the upper part of the water jacket to the 

 top of the tank. The heat from the engine causes circula- 



FIG. 311 CIRCULATING PUMP SYSTEM OF COOLING 



tion similar to that in a boiler. Another plan (Fig. 311) 

 is to provide some way for the water to fall through the 

 air and thus cool itself by evaporation. In this plan a cir- 

 culating pump is necessary. The third method is to 

 allow a stream of water to run continually through the 

 engine. The first way is the most economical and possi- 

 bly the most satisfactory where there is plenty of room 

 and no danger of frost. The second method is coming 

 into general use because it takes less space and does not 

 require so much water at once. All late portable engines 

 are equipped with this device for cooling. For stationary 



