212 Specific Heat of Saturated Vapours. 



the proviso that the value of taken must be that at 

 saturation. The value C must be replaced by K w , the 

 specific heat of saturated liquid. The difference between 

 and K w is certainly negligible at temperatures sufficiently 

 remote from the critical temperature, but it tends towards + 

 infinity as the critical temperature is approached. The 

 relation between the two quantities is 



K — C —T(SH\ i£- 



or K w may be given conveniently in terms of C w , the specific 

 heat of the liquid at constant volume ; 



t §). 



K,=a 



\dv/T 



ds 



ST' 



where s is the specific volume of the liquid at saturation. 



The values of K w obtained by Mathias for S0 2 are given 

 herewith : — 



t° c. 



K- 



AX10 1 . 



t° C. 



K w . 



AX10 4 



-20 ... 



4-0315 









20 







1 



110 ... 



+0-442 





-10 ... 



•316 









32 







1 



120 ... 



•470 





... 



•317 









40 







2-5 



130 ... 



•510 





10 ... 



•3195 









110 







4-5 



140 ... 



•620 





20 ... 



•324 









252 







6 



150 ... 



•872 





30 ... 



•330 









480 







8 



151 ... 



•920 





40 ... 



•338 









600 







9 



152 ... 



•980 





50 ... 



•347 









900 







12 



153 ... 



1-070 





60 ... 



•359 









2850 







13 



154 ... 



1-355 





70 ... 



•372 









4450 







15 



155 ... 



1-800 





80 ... 



•387 









10500 







16 



1555... 



2 85 





90 ... 



•403 











100 ... 



•422 



19 









I have added the increase per degree, A, in order to show- 

 that K for S0 2 is not a linear function of the temperature 

 even in a region remote from the critical region. 



