( 695 ) 



by introducing the value of /> from the empirical equation of state, 

 this gives 



Co — cv— -jry I ~'^ jT^^ 2 f/t^ y).v) 4 'dF \?.v 



1 d' a fvk\' 1 d' % rvk\ } 



6 dt' \XvJ 8 dt^ \).v^ 



for t = 0.897 or T = 273 and v = 1,020 we find 



C— cv= 0.0432 

 or, since at T = 273 cr= 0.1431 is 



c„ = 0.1863 

 The point corresponding to v = 1.02 and t = 1 in the liquid 

 region is now found. This was obtained by the aid of the equations 1) 

 and 2) Avhere the term I> must be certainly taken into account ; 

 we find 



IV. for t=l ?7y = 1.020 



n = nT, = — 42.10 X 10^ 



ho 



s— fr^.^ = — 115 X 10' 



If we now assume that at the same temperature the difference 

 between the specific heats at constant volume in the ideal gas state 

 and for the volume 1.020, is constant and equal to k, we have 



T 



Tk 

 Tk 



with which the following points for v:= 1.020 are calculated: 



V. for t = 0.864 Vy = 1.020 



,1 = — 53,6X10^ 

 s = — 145X10^ 



VI. for t = 1.314 V,, =1.020 



,^ =: _ 28X10' 

 E = — 33X10' 

 According to the numbers of Kuenen and Robson the first of these 

 two points lies on the liquid branch of the binodal line. 



The model PI. II fig. 3 is constructed from the values for tliese 

 points. 



The values of v used are 100 times the calculated 



j> >j " 'i " " '^ " " " 



g 10-' 



