644 



PROCEEDINGS OP THE AMERICAN ACADEMY. 



a limit that of an adiabatic cycle with the same ratio of compression.* 

 From this point of view, the locus of these first order cycles may be 

 called the "high efficiency fuel line" as it indicates the beginning of the 

 high efficiency fuel for a given value of P. 



The work curves for this type are shown in Figure 12, and they, 

 like the efficiency curves, have turning points on the high efficiency fuel 

 line. The curve W = is, as always, the same as the curve £1=0. 

 The other lines go off to the right with /* = 1 as an asymptote. 



aso 



450 500 



Q \n BTU 



200 250 300 



Figure 11. 



Ti/pe B. Efficiency. For isothermal cycles. The turning points of these curves 

 lie on the "high efficiency fuel line." (Cf. Figure 6.) 



An inspection of Figure 10 shows that, as far as efficiency is concerned, 

 it pays, in this particular case, to keep at least as far up the right hand 



* The formula can be put in the form 





C^Ta 



(lege P " - 1 + P « ) 



Q ' 



where 



Lira <p{P) _ 

 Q=oo Q ~ 



