742 



1. F melts with increase of volume. Tlie saturatioiicurve undei* 

 its own vapour-pressure disappears, when is raised the temperature 

 in // [fig. 4 (XI)] when the concentration of the new substance is 

 greater in the liquid than in the vapour. It does not disappear in 

 H [fig. 6 (XI)] when the concentration of the new substance is 

 smaller in the liquid than in the vapour. 



2. F melts with decrease of volume. The saturationcurve under 

 its own vapour-pressure disappears, when is raised the temperature 

 in H [Fig. 5 fXI), wherein however H must be situated between 

 F and B] 



3. The boilingpoiiitcurve disappears, on increase of P in Q 

 [fig. 5 (XI)], when the concentration of the new substance is greater 

 in the liquid than in the vapour. It does not disappear in Q [fig, 6 

 (XI)] when the concentration of the new substance is smaller in the 

 liquid than in the vapour. We mean of course, with ''concentration" 

 above "perspective concentration". 



Now we will deduce in another way the relations in the vicinity 

 of the point H or Q. The saturationcurve under its own vapour- 

 pressure is fixed by the equations (1) (II), when we put therein « = 



and when we keep 1 constant. As ^-,t — , etc. become infinitely 



great for .v = 0, we shall put 



Z=U -\- RTxhgx (I) 



so that all differential quotients of U with respect to ,r, remain finite. 



We put in the same way : 



Z, — l\ + RTx^ log.v, (2) 



so that the same applies to L\. Then we have : 



dZ dU dZ dU dZ dU 



= ^ RT {I + lor, x) ; ^=^ ; ^=:— =.F. (3) 

 ox ox oy oy oP oP 



and similar relations for Z^ and U.^. 

 The equations J (II) then become : 



hU dU 



.t-— + (i/-|?)— +i^7;.-t7+S=0 .... (4) 

 Ox Oy 



dx, dy, 



dU dU, 



— + i?r (1 + loy x) = ^M ^T (1 -[- log x,) ... (6) 



0^/ ~Ö3/, 



