{dT),=:^-^p and {dP),=^^~^^. . . (34) 



350 



When we call its coiiceiitration .r, llien we have: 



^ {Xx)y = Aj.?;, and 2 Q.x)ii = — ft, a;, 



so that, in accordance with (13) and (15): 



— RTL.v, , — RT 

 ---* and (dP)^ = 



Consequently in fig. 1 curve E proceeds, starting from point i 

 towards lower P and 7'. 

 It follows from (33) : 



Hence it appears that in fig. 1 curve E coincides with curve (L). 

 Also we may find (34) at once with tlie aid of (9) and (11). We 

 put viz. : 



JS" (;) =:= 1 + ;ij + A, = and JS" {Xx) = X^x, = 



so that ;i, ::= and A, = — 1. Hence it follows: 



:£{IH) = H—H^ and :E{XV)^V—V^, 



consequently for (11) the same value as in (34). 



When the new substance occurs in liquid and vapour with the 

 concentrations x^ and a\ then we have : 



in accordance with (29): 2 {Xx)y = X^x^ -f X^x^ 



and in accordance with (32) : -5" {Xx)h = — ^^x^ -\- (i^x^ 



so that {dT)x and {dP)^ are known again. We see that {dT)x is 

 negative, but that ydP)x may be as well positive as negative. Curve 

 E, therefore, may be situated in fig. 1 as ia or ib. 

 When we put: 



irt=H='' • <^«» 



then is 



2{lx)H = iiA'^-J^'^\) ...... (37) 



wherein, in accordance to (35), K^l. 



Now we find : 



.1', 

 for — ^ /r is (r/P)a;^0; consequently curve E goes, starting 



X, 



from point / towards higher pressures; 



X 



for — <^ /f is {dP)x <^0; consequently curve E goes, starting 

 from point i towards lower pressures. 



