Manchester Me^noirs^ Vol. xlviii. (1904), No. Tf. 15 



approximately equal tensile and compressive stresses 

 alternately. The horizontal set of parts is used merely to 

 balance the vertical set and thus reduce vibration. 



This machine is, however, limited in its rapidity of 

 alternations to about 2,500 per minute, owing to mechanical 

 and lubricating difficulties. Furthermore it can only give 

 alternating stresses approximately equal in amount, and 

 when running makes such a noise as to be a nuisance. 



The machine about to be described is designed to get 

 over these difficulties, and to possess other advantages to 

 be described later. 



Plan of Valve and Ports. 

 J^g. 8. 



It consists (Fi£-s. 8 cS- 9) of a piston P fitting into a 

 cylinder C Fixed in the cylinder is a transverse plate S 

 with ports cut in it. Resting against this plate and 

 rotating in the cylinder is the rotating valve V with ports 

 in the transverse portion and a second set in the circum- 

 ferential rim. The cylinder has a spacious steam chest B 

 and admission ports A. The valve is driven at the 



