^.= 



( 579 ) 



1 {i-.ry 



l+.r 2-.f + .t---' 



follows : 



^^ — 0,0472 ; [l^ = 0.0865. 



We liiul lor hJ),-. ') 



' '' 27 a; 1-/?, 



01' 



27 hk 0,9528 ^ 27 bj, h 



With ^/ = 3()(), A/. = 845 we find lliereroiv: 



wiiich gi\es: 



ET,, = 0,9994 ~^~- — 0,108, 

 ^ ' 273 



Tk = 29°,5 , 



Dewak foniid Tk=z'Mr a 32° ■'). 



The ei-itical pressure is represented by ') 



^ ^ 1_ a (l-^,-4^J( 14-2(/?, + /?J)-- 



01' 



1 a 0,8068X1,363 1 « « 



y>/,. = X -— = 1-154 X = 0,0427 — . 



^ 27 f>,/ 0.9528 21 h,:' h^' 



Inli'odueing into Ihis e\[»i'ession the values oi" (( and hf-, we lind : 



plc = 18,0 atm. 



Dewar found 15,4 alm.; ( )lzewski ") 20 alm. 



We find for Ihe S(> called erilieal eoefficiejil A : '') 



I T)rr 1. o '^ 



UTjk 8 -{l-^-^;f 



or 



3 0,8068 3 



A = — X^ = — X 0,961 = 0.360. 



8 ^0.8396 8 



Finally Ihe tpiaulily V may l)e calculated from ") 



1) Id. Il, p. 583. 



2) Proc. Royal Insl. 16 (^i), N". 91- (1001), p. 177. 

 ■■■) V. D. Waals, 1. c. II, p. 5S3. 



') Wied. Ann., 56, jk 133 (1S95). See also Vkhsciiafkki/i', Tliese Proceeding.*!, 

 Febr., 1899, p. 3"i7. 



■'') V. D. Waals, 1. e. II, p. .jSi. 



«j ld. III, p. Gi8, 



