ENGINE No. 61. 



Double valve, 6" x 14". Speed, 210 revolutions per minute. 



This is an automatic cut-off engine with slide valves and 

 shaft governor. The main valve is of the box pattern, with 

 balance plates on the back face. Steam is admitted into the 

 interior of the box before it passes through the ports into the 

 cylinder. The cut-off valve rides on a seat inside, and is 

 operated by a separate eccentric, which is shifted by the action 

 of a shaft governor. The diagrams here given show the effect 

 of moving the eccentric which operates the main valve an 

 angular distance of 43 on the shaft. This represents a dis- 

 tance of H" on a shaft 4" in diameter. No. 61a was taken 

 before, and No. 616 after, the change. 



ENGINE No. 61a 



ENGINENo.61b 



281 



