134 Mr. J. Rose-Innes on the Practical Attainment of 



thoroughly than those of any other gas. (See Kelvin's 

 Reprinted Papers, vol. iii. p. 183.) 



The following values of the coefficients tf ? a i> a ^ nave heen 

 calculated : — 



Hydrogen. 



a - -0009613 Y 



a L -05798 V 



a 2 28'94V 



Nitrogen. 



-•002511 V 

 1-4281 V u 

 105-42 V 



Air. 



•002095 V 

 1-3270 V 

 52-365 Y 



Here Y is the volume of 1 gramme of the gas at standard 

 temperature and pressure. 



The following table enables us to estimate the accuracy with 

 which the experimental results are reproduced by the formula. 



Hydrogen. 



Joule-Thomson Effect 

 per 100 inches of Mercury. 



Observed. 



Calculated. 



At 4°5 C 



-o-ioo 



-0155 



•00078 



-o-ioo 



-0-155 



•00078 



At 91° C 



Value of (v^ at 50° C. ... 

 \djpjt 



Nitrogen. 



Joule-Thomson Effect 

 per 100 inches of Mercury. 



Observed. 



Calculated. 



At7°-204O 



1-034 

 0-576 

 0691 

 - -00035 



1-034 



0-576 



0-574 



- -00035 



At91 415 



At91°-965C 



Value of ( d -^\ at 16° 0- ... 

 \apjt 



Air. 



Joule-Thomson Effect 

 per 100 inches of Mercury. 



Observed. 



Calculated. 



At 0° C.... 



•92 

 •88 

 •75 

 •51 

 -•00041 



•878 



•713 



•510 



- -00041 



At7°T C 



At39°-5 C 



At92°-8C 



Value of (*h at 16° C. ... 

 \dpjt 



