( 286 ) 

 .v^—x^ MET \ /dp 



'1 ^2— ^lA K^'cJot' 

 If at lower temperatures the initial direction of the j^,ci'-line is 

 traced for the liquid phase, and also that for the vapour phase, then 

 these directions are usually different. Between these two directions 

 lies the direction for the line which denotes the course of the quan- 

 tity jJc- If this last line is an ascending one, this is also the case for 

 the two others, and reversely. If the admixture is called more volatile 



1) Though it falls outside the scope of our subject, which only treats of 

 projjcrlies on the side of the surface of saturation, I will make a single remark 

 on the mixtures for which liquid and vapour have the same concentration, 

 because these mixtures have many properties which the components also 



possess. Also for these mixtures the equation: MBTl—= I I ^- I dv,ov 



MRT I— \ ^ \ holds. For these cases — = 1 and so K- = 0. So for 



a^ \divJ„T '^i yJ'VjoT 



a mixture for which this equation would hold at the critical circumstances, 



I ^ I itself would be equal to 0. As also ::— ^ :r— r- = v^ must be equal to 0, 



\dxJ„T ^^^ Ou" \dxJvT 



also Mr — 0, and from; 

 ovJvT 



follows : 



dp = ^^ dv^i^A ^•^• + fr^l dT 



OVxT V"'Vyr \0TJux 



dp / dp 

 dT~[df 



Already in 1895 I made the remark, which follows from this, viz. that for the 



point of the plaitpoint curve, at which the line which is sometimes called the line 



of KoNOWALOw, meets the plaitpoint line, contact must take place and that just 



T dp . ^ 

 as for a simple substance — r;=, = is about 7. 



p dl 



fèp\ 

 Now I will add that from s~ =0 follows in the same way, as has been 



derived above, that: 



d log Ty \ dloq b 



^^ _|- _ ^_ — IS, 



dx 6 dx 



d loq Ty \ d loq h 



— ^- — 1 ^ -L^ = 0, 



dx 3 d,v 



and not 



as would follow when b is |)ut constant. Already Quint pointed out that the last 

 equation was not satisfied in his observations. According to an oral communication 

 the equation given here would be in much better harmony with his observations. 



