RULES FOR CALCULATING THE STEAM ENGINE. 221 



parallel bar ; and by subtracting it from the horizontal distance of the centres we get the 

 length of the radius rod. (233.) 



Example. Taking the same case as that of the preceding rule, we shall have the radius of 

 the beam 64 inches, the length of stroke 42 inches, the radius rod connected 68 inches 

 from the beam, the piston rod connected 84 inches from the beam, and the horizontal 

 distance between the centres of the radius bar and beam 20-08 inches, to find the 

 suitable lengths of the parallel bar and radius bar. 



Beam 64 Stroke 42 



68 68 



512 336 



384 252 



84) 4352 (51-81, prepared beam 84) 2856 (34, prepared stroke. 

 420 252 



152 336 



84 336 



680 * 



672 



80 



Beam 51-81 Half stroke 17 



51-81 17 



5181 119 



41448 17 



5181 

 25905 



2684-2761 

 289 



2395-2761 ( 48-94 - ... 48'94 



16 Hor. dist. I OA AQ Beam 51-81 



centres / 2( 



881795 100-75 



4 Half beam 25-9 



90675 

 8721 50375 



9784 I 40661 2015 



2609-425 



