ENGINE No. 68. 



Four valve, 13" x 36". Speed, 61 revolutions per minute. 



This engine has double poppet valves for admission, and 

 slide valves for exhaust. The valves are operated by a train 

 of gears and cams. The adjustments consisted in moving for- 

 ward the cam which operates the steam valve so as to produce 

 earlier admission. The diagrams are taken from the head end, 

 No. 68a before, and 6Sb after, the changes. 



ENGINE No. 68a 



ENGINE No. 68b 



289 



