370 



PBOF. C. FEEWEN JENKIN AND ME. D. K. PYE ON THE 



pressure curve, cutting the I = 55 line in A., and the limit curve in L. We have to 

 find the point P on this curve where I = GO. 



1 = 55 



With the notation in the figure 



Again . 

 and also 

 Therefore 



m d,j, = 



do = Ii 



Having found dO, the point P on the pressure curve is marked off. Similar points 

 are found on the other pressure lines and joined up, thus forming the required I curve. 

 Points on all the curves after the first are plotted, each from the one before, by means 

 of the equation 



,18 = 5 Th - U - . 



APPENDIX III. 



Modifications Produced in the 9<f> Diagram by a Correction in the Values 

 Accepted for the Total Heat of the Liquid C0 2 . 



If the line AB represents the constant-pressure curve, p = 700. Ib. per sq. inch, 

 then the area MABN under this curve down to absolute zero represents the heat 

 required to raise the temperature of 1-lb. of CO 2 at 700-lb. pressure from A to B , i.e., 

 the total heat from A to B . If the total heat were assumed to be 5 per cent, less, 

 then A would have to be shifted to A', where A A' is 5 per cent, of AQ, i.e., about 

 0'005 carnots at -50 C. The limit curve, which is set off from the constant-pressure 



