(22) 



348 



from the figs 1 and 2. It follows tVom the position of the curves 



in fig 1. 



towards lower 7'! towards higher T 



\ .... (21) 



F'^h\-G AHyO AV=0 



and 



towards higher F \ towards lower F 



L-^F^G AH=0 AF>0 



so that both reactions are known qualitatively. 



Now we add to this equilibrium E (a; = 0) = F -{- L -[- G a. sub- 

 stance, which occurs in the liquid only. As in the isovoluraetrical 

 reaction (21) L is placed at the right side of the reaction-sign, 

 consequently, in accordance with our rules, T is lowered; as in the 

 isentropical reaction (22) L is placed at the left side of the reaction- 

 sign, the pressure is also lowered, therefore. 



Consequently in fig. 1 curve F proceeds starting from point i 

 towards lower T and F; this is in accordance with the deduced 

 above, that curve E coincides with curve (L) in this case. 



When we add a volatile substance, than it occurs in L and G. 

 As both those phases are placed in (21) at the right side of the 

 reaction-sign, consequently T is lowered. As L and G are placed 

 in (22) at different sides of the reaction-sign, the pressure may be 

 as well increased as decreased. Therefore, curve ^may be represented 

 by ia or ib in fig. 1. Which of these curves may occur in a 

 definite case, cannot be deduced in this, manner; we are able to do 

 this, as we shall see further, with the aid of the quantitative reactions. 



In order to deduce the qualitative reactions from fig. 2, we write: 

 towards lower T\ towards higher T 



(L) I {F) {G) 



F + G:^L A^>0 AF=0 



(23) 



and 



towards higher P 



towards lower F 



(24) 



(F) (G) (L) 



L-^F ^G AH = AF>0. 



When we aid a new substance, which occurs in L and G, then 

 we find that curve E may be represented in fig. 2 by ia, ib or ic. 



It is apparent from the previous that by simple considerations 

 we may deduce already something about the direction of curve E 

 from the qualitative P, 7^-diagram of an invariant equilibrium E(x = 0). 



