R0< MBLE KNfilNCER: IJI 



A I g steam at a low pressure 



a condenser, producing a vacuum, the piston 

 !cr steam pressure on one side and vacuum on 

 the other. 



Q. What class of engines are farm engines? 

 A. They are high pressure. 

 Q. W 



A 1 : r arc less complicated ant! less expcns: 

 Q. What is the most economical pressure to carr 

 a high pressure engine? 



A. From 90 to no pounds. 



Why is high pressure more economical than low- 

 pressure ? 



\. Because the loss is greater in low pressure owing 

 ie atmospheric pressure. With 45 pounds steam 

 the pressure from the atmosphere is 15 pounds, or one- 

 third, leaving only 30 pounds of effective power; while 

 with 90 pounds the atmospheric pressure is only one- 

 h of the boiler pressure. 



Does it require any more fuel to carry 100 poi 

 than it does to carry 60 pour 



It 'Vr-iu require quite a: much. 

 Q. If that is the case why hot increase the pressure 

 beyond this and save more fuel? 



Because we would soon pass the point of safety in 

 a boiler, and the result would be the loss of life and prop- 



