ENGINE No. 75. 



Four valve (Corliss), 30" x 48." Speed, 80 revolutions per 

 minute. The setting of the valves was changed by the intro- 

 duction of a separate eccentric for driving the exhaust valves, 

 and the adjustment of this eccentric so as to obtain early 

 compression. With a single eccentric the engine operated 

 unsatisfactorily on account of the noisy action of the piston 

 and valves, there being decided and annoying sounds at each 

 end of the stroke, which could be distinctly heard by a 

 person standing at a distance of 20 feet from the cylinder. 

 When the additional eccentric had been applied and the valves 

 readjusted, the troublesome sounds so far disappeared that it 

 was necessary for the observer to hold his ear close to the 

 cylinder to be aware of any disturbance. The diagrams were 

 taken from the head end, and for ready comparison, they are 

 superimposed, the full line being taken with single eccentric 

 and the dotted line after changing to double eccentrics and re- 

 setting the valves. 



ENGINE No. 75 



296 



