1139 



In (12) A^ indicates the saiiie denoiiiiiiatoi- a,s in (11). 



Let ns now consider the case that both the solid substances of 

 the equilibrium F -\- F' -\- L -\- G are binary compounds of 7i and C. 

 We must then put « ^ and a' = 0. As E becomes = (/i' — /?) x 

 and E, = {^' — ^) ,i\, it follows from (10), ^11) and (12): 



X, 



dp 

 df 



dp 



dx 



dT 



d.v 



^Hr 



(13) 



^1.. — - v^ 



X 



{rt—s^)x\ H\,:, 



-^S 



{V:,Hl.,— Vi,:,H,)t 



(rt-B')x[ Fi..,~-ir, 



X 



(14) 



(15) 



Let us now consider the terminating point of the ternary equilibrium 

 F -{- F' -\- L -{- G m the quadruplepoint F -\- F' -^ L,-{- G,. For 

 this we make in the previous equations x and x^ approach to zero. 

 As Limrx^=z RF it follows: 



dP 

 dT 



X 



Hx 



dP 

 Herein 



RT 



Hi. 



/^) H. 



^-G)/^ 



(16) 



VxHi.:,-Vi,,H:c 



is the value which 



dr 



dx 



RT 



v^.-n 



Vr 



(17) 



assumes for x = and x, = 



Further is : 



(^' 



wherein to all quantities {j/.j/i, V, F^, etc.) we must give the values, 

 which they have in the quadruplepoint F -{- F' -\- L, -^ G,. Herein 

 Xo has the composition: ?/ quantities of B -\- {;i ~ y) quant, of C ; 

 G„ has the composition : y, quant, of 5 + (1 — i/,) quant, of C. 

 Between the three phases F, F' and L^ always may occur the reaction: 



^) V ^{y —^')v -}-(ii-y)v' = {,ï — ii) V, 



^) Vr + (ih - ^^') V + (/? - ;/,) v' = (/?' — i^) Vi., 



,?) // 4- {y _ ^') ,i + (^ _ ^ ) ,^' = (^?' __ ^) H, 



/?) ^1 + (2/i - /?') 'i + (/? — .Vx) 1/ = (/?' - /?) //l.. 



(18) 

 (19) 

 (20) 

 (21) 



