( 294 ) 



Lh Ab 

 a suitable value of calculated Iroui if = (l-f--^'^) • li ^ve 



wanted to consider .v, jj, and fp as univuown quantities, so that the 



Lh 



value ot was of course determined, the knowledge of a third 



r — b 



quantitj' would still he required at the critical point. This third 



quanlit}' could be no other than the direction of the so-called "straight 



diameter" in the critical |)oint. But as the discussion of this calls 



for a separate study, which we hope to give in a following Paper, 



we shall now content ourselves with the kuowledge of fj and/', and 



Lh 

 simplv examine at what \alue of ./■ a suitable \'alue of is 



r — h 



obtained with the calculated values of ,i and '/ . 



4. Let us in the first place examine what the approximate formula 

 (10") for ƒ teaches us concerning the values of the quantities ^y? and ?z. 



From f=\ -\ follows: 



_ '7," _ è^' \vk 



p,[- 1 a \Sm^ — 2n)' (4?i — 'Sm) 



'21 bt' 



b/,- . 3m" — 2n 



or as — is = — : — ^ — , according to ((3; : 



o 



om 

 4?< — Ó7n 



f — 1 'ó)n 

 or also' — r= — . ie. 

 / 4/* 



in 



4 /-I 



. . (") 



n S J 



If we now assume a "mean" normal substance, for which the 

 value of/' maj be put to be 7, we find for the ratio ?/i : ?i the value 



m _ 8 

 n 7 



After division bv 1 -]- ,c, 



3 \+x3m' f m\ 



14- -f n \ n J 



follows from (9\ as we Shall regard the value of V]- in — — as referring 



to simple molecular quantities. 



