362 PROF. C. FKEWEN .TENKIN AND ME. D. E. PYE ON THE 



The liquid from the weighing flask passes through one coil in calorimeter II. and then 

 through the 1-inch calorimeter, then through the inner coil of the interchanger and 

 expands through the valve V into the second coil in calorimeter II. ; from there it 

 passes through the outer coil of the interchanger, through the drying flask to the 

 pump. The liquid is cooled to the desired starting temperature in calorimeter II. It 

 is then warmed through an accurately measured range of temperature in the 1-inch 

 calorimeter by the accurately measured electric power. The warm liquid is cooled in 

 the interchanger and then, by expanding through the valve into the second coil, cools 

 the calorimeter II, thus supplying the refrigeration required to cool the liquid in the 

 first coil. The cold gas passing out of calorimeter II. serves finally to cool the liquid 

 in the interchanger and then passes to the pump. 

 The quantities measured were : 



The rate of flow of the liquid CO 2 . 



The rise of temperature of the liquid in the 1-inch calorimeter. 



The electric power supplied to the 1-inch calorimeter. 



The results of the experiments are given in Table D, arranged in the same way as 

 in Table. IIT., of the former paper. The new results have been used to correct the 

 liquid-limit curve on the 0</> chart (see fig. G), where the full line is the new and the 

 dotted line the old curve. The maximum correction, at 50 C., amounts to 0'0054 

 carnots and decreases to zero at 20 0. 



A correction of the limit curve produces a very small correction on the I lines, as is 

 explained in Appendix III. The I lines have been shifted 0'0005 to the right at 

 50 C. too small a distance to be shown in the figure. 



Throttling Experiments on Superheated (if as. 



Throttling experiments are simple and quickly made. The only four quantities to 

 be measured are the pressures and temperatures before and after the throttle valve. 

 The rate of flow is immaterial ; it is only necessary to adjust the apparatus till the 

 conditions are steady and then to take the four readings. The throttle valve used 

 in the new experiments was the same one that was used for the experiments on 

 throttling the liquid C0 2 described in the former paper (Series IV., p. 91). 



The arrangement of the apparatus is shown in fig. 7. The liquid C0 2 coming from 

 the weighing flasks expands through the valve Vj into the 2j-inch heater where it is 

 evaporated and then passed into calorimeter II., where it is warmed to the required 

 initial temperature. It then passes through the special throttle valve where the 

 pressure falls to the required lower pressure, and so through the drying flask to the 

 pump. The valve V 2 serves to regulate the lower pressure when necessary. 



The results are given in Table E where each line of experiment is denoted by a 

 letter (column l). 



Columns 2 and 3 give the standard initial and final pressures. 



