853 



^ r= U -\- HT{x log X -\- y log y)diïi& Z^z= U ^ \- RT {x^ log x^ -f y^ log y^) 



We tfien find for the equilibrium B -\- L -\- (r in the vicinity of 

 the point B when we put x = _^ .^•, -rrz §^ y z= i^ y^ = t^^ F z= Pn ^ dP 

 and Tz=Tb + dT -. 



RTl + RT"i\ — ( V-.v) dF 4- (/ƒ— rj6) dT=() . (9) 



RTl + RTii^ - (r,-r) (ii> + {ll,-nb) dT=0 \ 



Herein, in order to distinguish' the coordinate r], the entropy of 

 the solid substance B is represented by i]t,- 



In order to examine the influence of tlie pressure on the position 

 of tiie boilingpointcurves, we ehminate from (9) c^?'. We then obtain: 



BC—AD 



gLW^+ riLW,, = dP .... (10) 



wherein BC — ADy^. (See Comm. 11). 

 Wlien we put in (10) dP = 0, we obtain : 



%LW,-\-^LW,i= (11) 



the boilingpointcurve going tiirough the point B. 



At tirst we take Air^ and Air^ negative, so that the case treated 

 sub c occurs (fig. 4 — 6). From (IJ) it follows that | and ^^ have the 

 opposite sign ; the boilingpointcurve of the pressure Pb is situated, 

 therefore, excepted in the point B itself, completely outside the 

 triangle. 



In figs 4 —6 a similar curve going through the point B is dotted 



and a curve situated in the vicinity of B is extended outside the 



triangle ; these parts situated outside the triangle have of course no 



meaning for us. The direction of the boilingpointcurve going through 



x^ y^ 

 the point B, is fixed by L W^; and A W,^ ; if accidentally — = — , therefore, 



X y 



also ATFjzzzATr/y, then this curve runs parallel to AC. 



We now take a pressure somewhat higher than Pb, therefore dP 

 positive; the second term of (10) is, therefore, negative. From this 

 it follows that the curve cuts off" a positive part i] from the 1^-axis 

 {BC) and a positive part ê fi'om the A-axis {BA), the curve is 

 situated, therefore, partly within the triangle as in figs 4 — 6 the 

 curve in the vicinity of B, partly drawn and partly dotted. In 

 accordance with what was treated sub c (figs. 4 — 6) we find, there- 

 fore, that the boilingpoint curve shifts on increase of P from the 

 point B into the triangle. 



In the same w^ay it is apparent from (10) that under a pressure, 

 somewhat lower than Pb, therefore for dP negative, the curve cuts oifa 



