374 



PROF. C. FREWEN JENKIN AND MR. D. R. PYE ON THE 



have to find the temperature of U, i.e., the temperature which would have been 

 observed if the conditions had been standard. 



With the notation in the figure 



Similarly, 

 and 



dt a = (^) i dp. 



7T 1 "*1 7"P 



al a = alj. 



The required temperature of U, 9 a = 6 K + dt. 2 + dT 2 . 



The values of ( -. - ) were measured from the 00 chart and plotted against tempera- 

 \dpji 



tures, and it was found that for the range covered by the experiments the values 

 were roughly constant for any one temperature (i.e., independent of pressure). They 

 may, therefore, be given with sufficient accuracy as follows : 



