( ifio ) 



for increasing valne of 7 ; and so wo arrive at a t'onclusion, to 

 which I came ah-eadj before, \'iz. that the concentration of the 

 maximum value of /> in the p, ,v curve is sufficiently the same as 

 that of the mixture with minimum critical temperature onlj for the 

 very lowest values of T. It only appears that already at ordinary 

 temperatures the shifting mentioned above may be rather considerable. 

 A consequence of this is, that the shifting between the ordinary 

 temperatures and T r= Tt may be only slight. This shifting is however 

 the greater as the ditlerence in the size of the molecules is the more 

 considerable, and as the dcci'case in critical temperature takes place 

 the more slowly. 



Now^ that we have found an approximate value for [l,^■, wt can 

 immediately derix^e from it an api)roximatc value foi' \.i\, a quantity 

 which must be known, if in the equation : 



the factor of dx^ is to be considered as known. We have viz. 

 ^%\ i 1 ) 



We lind theji 



a a 



1 /> ¥ 



or 



^*' ~ Mirrdr' "^ dn:' ' 



^* ■' ~" T d.c' "^ civ' 



So for small vapour pressure the equation: 



I A//> \ _ \ 1 ƒ ^Tfc cl^pk^] 



holds approximately. 



fP Tj. 

 Tn general the quantitv — -^ will be positive, and this is certamly 



^ ' • d,v^^ 



so when there is a minimum value for 71-; the value of the other 

 term may change this of course. But as a rule ft".,, will be found 

 neaative for normal substances. 



In the value of the quantitv -(^7,) only one of the two parts 



of u'r occurs, viz. and not the other part -— - . bo only the 



^ ' T dx, «'''i 



part depending on 7' is kept. In different ways the value of this quantity 



