349 



Wlien, however, we know the quantitative reactions, then we are 

 able to deduce not only the quantitative /^7'-diagram for the equili- 

 brium E{x = 0) but also {dT)x and {dP)x for the eqnilil)riuui E 

 and consequently we can define exactly the direction of curve E. 



When we represent entropy and volume of F by H and V, of 

 L by H, and V, and of G by H, and F,, and when we assume 

 that the substance melts on decrease of volume, then we have: 



H^yn.yH and F,>F>F, . . . . (25) 



We write the isovoluraetrical reaction : 



F + }.,L-\-X,G = (26) 



As, in accordance with (12) : 



1 + A. +A, = and F+A, F, + A, r, = . . (27) 



it follows : 



V —V V— V 



•^ J "^ 1 "^ » ' 1 



SO that vlj and ;i, are both negative. Instead of (26) we now write: 



F:^X^L +X^G (29) 



wherein 



V — V V— V 



and 



2(kH)v = ),H, + KH,-H (31) 



Now we may prove that ^ {lH)v i^ generally positive, so that, 



on addition of heat the isovolumetrical reaction (29) proceeds from 

 left to right. 



In a similar way we find for the isen tropical reaction : 



li,L:^F-^li,G (32) 



and 



2 {XV)h =V -\- ii,V, - ^,V , 



wherein 



''' = HrrH, '" ''•^irr-^, ■ ■ ■ ■ '''' 



SO that fij and /it, are both positive. 



As ^(AF)£z^is positive, reaction (32) proceeds from left to right 

 with increase of volume. 



With the aid of reactions (29) and (32), as is discussed in previous 

 communications we now can deduce the P,T-diagram quantitatively; 

 then we find fig. 1. 



Now we add a new substance which occurs in the liquid only. 



