SCIENCE OF THRESHING. 143 



reduced, and as a result, the engine will be stalled, 

 and there may be trouble in getting it started again 

 while on an incline. The reduction of the steam 

 pressure so suddenly while a hot fire is burning is 

 very liable to cause foaming or priming, and is also 

 hard on the joints and weak portions of the boiler. 

 The proper plan is to watch the steam gauge closely 

 and keep the speed only fast enough to maintain the 

 steam pressure sufficiently high to insure the working 

 of the engine. When the engine is working at its 

 fullest capacity, the reverse lever may be thrown 

 over to the last notch on the quadrant to permit the 

 cylinder to be filled with live steam during the great- 

 est portion of the stroke possible, and thus prevent 

 the engine from becoming stalled. 



In passing down hill, the reverse lever may be 

 hooked up near the center. If the hill is so steep 

 that the engine has a tendency to increase its 

 speed, the throttle should be closed and the engine 

 should be reversed; the piston will then cushion 

 itself on the air in the cylinder and so retard the speed. 

 In case this is not a sufficient check, the throttle may 

 be opened slightly to admit a little steam and the 

 reverse lever moved to a point where the desired 

 speed of the engine will be maintained. 



While on the road it is poor practice to take off the 

 governor belt and try to control the speed of the 

 engine by the throttle or to run it at a greatly 

 increased rate, as the vibration and jar of the oscil- 

 lating parts cause strain and undue wear on the 

 connecting parts. If it is desired to change the speed, 



