372 



PEOF. C. FKEWEN JENKIN AND ME. D. E. PYE ON THE 



We have 



IB = I, 



(i) 



and I A = Iji + a-i(0 A 9 C ), where o-j is the specific heat of the gas at A, and I n , on the 

 limit curve, is known. Let K be the point on the limit curve corresponding to p 2 and 

 let d<f> be the horizontal distance between K and B. 

 Then 



= -IK H 



0_L A* 

 B -T "K 



- 



_ T 



A ' 



an equation giving d^ and thus fixing B. 



Choosing the next experiment, starting at A', we find the point B' by equating 

 I A . I A = I B < IB- and so on. 



Joining up the points B, B', &c., we have the constant-pressure curve corresponding 

 to the pressure p 2 derived from the throttling experiments. A similar construction is 

 used to plot the throttling results corresponding to all the other pressures. If the 

 chart is correct the curve B, B', B" will coincide witli KL, the constant-pressure curve 

 plotted through K by means of the observed specific heat of the gas. 



APPENDIX V. 



A Method of Plotting the Gas-Limit Curve from the Results of a Line oj 



Throttling Experiments. 



The limit curve is plotted by finding the points where it cuts successive pressure 

 curves. Let A (Oipi) and B (0 2 p 2 ) represent the initial and final conditions of the 

 gas in one of the lines of throttle experiments. COA and DPB are the pressure 



