509 



Then hk becomes: 



2,686X23,0 61,78 



bk = — . —-^— — 265. 10-5 



1,041 X 22412 23330 ^ 



2,580 X 23,0 59,34 " , 



or bk=— =:—^—=: 251 . 10-5 



1,056X22412 23670 ' 



We find for ak: 



1970x26,5.10-4 52210 



a/, = ——^ = 10-t=: 708,7. 10-4 



73,67 73,67 



1730 X 25,1.10-4 43420 \ 



or ak = = 10-4=583,8.10-4 



^ 74,38 74,31 



so that we have \ ak = '26,Q to 24,2.10-2. 



We calculate for the critical pressure : 



1970 1970 



Pk 



2185X265.10-5 5,790 



= 340 atm. 



1730 1730 



or vh = ■ — ■ =■ — - — = 315,5 ,, I 



^^ 2185 X 251.10-5 5,484 I, 



which renders log'' pk = i'vom 2,532 to 2,499. 



The found values of y, viz. 1,34 to 1,29, may be tested, however 

 little, by the experimentally found value of the coefjicient of expan- 

 sion a in liquid state. In order to reduce « to y we can derive the 

 following relation. From 



follows immediately : 



1 1 



r, 5JlA 1 D-D, 



a z=z JJ z= ~— , 



t—t, D, t^-t^ 



so that the quantity y' in D^ — Z), = y' {t, — t^) is found from 



y' 

 y' = « X D^, or a from a = -^ . 



Now (reduced) d^ — r/j =:: 2 y (?/i, — m^), when the vapour densities 

 can be neglected, hence as d=D: Dk and m=T: Tk, edso D^-D^ = 



— 2y -i'(7', — r,), so that we have: 

 Tk 



Dk 



2y^', 



and 



