148 SCIENCE OF THRESHING. 



follows: Place the engine slightly off the center in 

 the direction it is intended to run, a sufficient distance 

 to insure the steam port being open to admit the live 

 steam to the cylinder; take a strong chain and fasten 

 to the rim of the flywheel adjacent to one of its 

 spokes, and secure it to some stationary part of the 

 engine in such a manner that when the throttle is 

 opened, and steam is admitted to the cylinder, the 

 flywheel cannot revolve, but resists the pressure of 

 the steam on the piston. With the engine in this posi- 

 tion and the throttle open, we have full boiler pres- 

 sure on one side of the piston and the other side 

 exposed to the atmosphere through the exhaust ports 

 and pipes. By placing the hand over the exhaust 

 nozzle, at the base of the smokestack, any leakage of 

 the steam through the cylinder rings or valve seat 

 may be easily detected. If much steam is escaping, 

 the valve seats and rings should have attention; 

 however, the most perfectly fitted engines will leak 

 some. 



If the engine is found leaking, the next step is to 

 determine whether it is through the valve seat or 

 cylinder rings. This may be done as follows. Place 

 the engine slightly off the exterior dead center in the 

 direction intended to run, which will open the steam 

 port at the crank end of the cylinder. Chain the 

 flywheel as before and remove the cylinder cap. 

 With the engine in this position and the throttle valve 

 open, and steam pressure on the valve and on the 

 piston in the crank end of the cylinder, the point of 

 leakage can be easily detected. If the steam escapes 



