(35 ) 



As <9 = jt 4- « (" — h) = a V — /? [/a passes into av for ^ = 0, we 

 may write for (1) : 



RT = — 



X (1 — x) a\' + a (u — by 



and (2) is reduced to: 



.r(l - .v)a'v' [(1 -2.^>] -4- [/a{v — by 



S.v{l-x) a'v' -f a (v-b) (v-36) 



• (1«) 



0. (2«) 



Let us put these equations into a more homogeneous form. 



As a=z[\/a^ -\-x{\/a, — V'ai)]^ == (l/ö^i + .^'«)^ we may write for {la) ; 



RT = — 



V 



_2« 



If we now put : 



X (1 — x) a' -[- {[/a^ + A- «)M 1 — 



l/«l 



= y 



ct>, 



this last equation becomes: 



RT = — o) 



b 



.r(i-^-) + (^ + .^-r(i-^r 



Let us now introduce the "third" critical temperature T^. This 

 temperature is the plaitpoint temperature at v z= h, i. e. that at which 

 the limiting curve lying in the limiting plane v ^=h (see fig. 1 of my 

 previous paper cited above) reaches its maximum, and is represented 

 by {iO = l): 



2«' 



RT^ = Ac (1 — A'c) ^— . 







But as in the case h^ = b^ for Xc the value ^j is found (the 

 maximum of the now parabolic curve), we get : 



RT„ = ^^— . 



Our equation for RT becomes therefore 



RT = 4. RJ\ to 



X (1 - x) + (^ + xf (1 



-^- 



And if henceforth all temperatures are expressed in multiples of 

 Tq, we have finally, putting 



T 



r z=z 4 oj 



x{\ _ .t.) 4- (y + .^.)^ (1 -ayy 



(lb) 



3* 



