352 



so that the direction of curve E is defined. 



Also it is apparent from (39) that E must be situated between 

 the curves {F) and (L). 



Finally we shall assume that tlie new substaiice divides itself over 

 the three phases, we call its concentration in F L and G x x^ and 

 x^. We now have according to (29) and (32): 



2 (;..j;)k = — .r -h A,.r, + X^x^ and 2 {Xx)n = X — (i^x^ + (i^x^ 

 wherein X^ -{- ).^ =: 1 and fi^ =: 1 -\- ft,, so that {ilT)^ and {dP)x are 

 known. 



We now put: 



:S{Lv)y =r and :E {).x)h = -'< (41) 



As we are able to satisfy (40), independent on the values of 

 ?' and s, by positive values of x .I'j and .r,, it follows that curve E 

 may go in every direction starting from point i. It may be situated, 

 therefore, not only in one of the regions F and G, but also, like 

 f. i. curve ig, in the region L. Of course its situation is dependent 

 on the partition of the new substance between the three phases. 



The same considerations as for fig 1 are also valid for fig 2, for 

 this we have to examine however more in detail the occurrence ot 

 curve ic. 



Instead of (25) we have for fig 2 : 



^, > ^1 > ^ and F, > F, > F . . . . (42) 

 As A, is negative now, in accordance with (30) the isovolumetrical 

 reaction passes into : 



F -\- X,G:;t^,L (43) 



wherein: 



V^ — V ^ ^ V,-V 



and X„ = 



* V — V ' V — V 



so that 



2{XH) — ).^H^ — H — X^G 

 is generally positive; reaction (43) is proceeding therefore, on addi- 

 tion of heat from left to right. 



When we now aid a new substance, which occurs in liquid and 

 vapour, then we have: 2 {Xx)v^= '>-vi\ — ^jVj. In order that {dT)x 

 is positive, 2{lx)v must be negative, consequently: 



J>J, - 7>^—y <") 



As in general V^ — V is some thousand times larger than F, — V 

 curve ic therefore can, occur only in the very special case that the 

 concentration of the new substance is some thousand times larger 

 in the vapour than in the liquid. 



