856 



pointctirve from its terminatingpoiiil on the .V-axis (^^4) by clTjc, 

 we find from (13) : 



LW, . dT, = RT'l^-'^]i] (15) 



V ■^' y J 



Let us firstk consider fis- 3, in the vicinity of the point i? of this 



Wrxu'Q is A W,, < and L W,- > 0, therefore — >- . From (14) 



and (15) it now follows that OT,, and (17^ are both negative. This 

 means that on a boilingpointcurve, situated in the vicinity of B, 

 the temperature decreases from the levminatingi)oint situated in the 

 vicinity of B. This is in accordance with fig. 3. 



In fig. 4—6 we will assume --> -Mn order to remain in accord- 



y •^■ 



ance with the direction of the boilingpointcurves, situated in the 

 vicinity of B. As A W,^ and Zl W.r are both negative, it follows from 

 (14) and (15) that (H\<^0 and r/7'r>0. On a boiiingpointcurve 

 situated in the vicinity of B the pressure, therefore, increases from 

 the terminatingpoint on BA ((/7'r > 0) and it decreases from the 

 terminatingpoint on BC (r/J[y<0). In conjunction with the length 

 of the parts, cut off by the curves from the sides BA and BC, we 

 may express this also in the following way : along a boiffngpoint- 

 curve situated in the vicinity of B the temperature increases in that 

 direction, in which this curve comes nearer to B (fig. 4 — 6). 



In the case sub a A ir^ and L IV;/ are both positive, we now 

 find the same rule as above foi" the change of temperature along a 

 boiiingpointcurve situated in the vicinity of B. 



We may give a short resume of some of the pi-evious results in 

 the following way. For this we assume that in the equilibrium 

 golid 5 -|- liquid /j -f vapour Z? the limit-ratio of 6' is greater than 

 that of A. 



a) The two binary 7^, ^-curves proceed from the point B towaixls 

 lower pressures ; consequently no point of maximumpressure occurs 

 \L ir.,>0 and A IF,, >0,; case sub r/]. A boiiingpointcurve situated 

 in the vicinity of B cuts off from the side BC a greater part than 

 from the side BA. The curve comes on decrease of F within the triangle. 



6) One of the two binary P, 7'-curves proceeds from B towards lower 

 pressures and one towards higher pressures, consequently one j)oint 

 of maximumpressure occurs [A TF^ > and A TFy<0; case sub /;. 

 fig. 3]. The boiling[)ointcurve cuts off under pressures, somewhat 

 higher than Pb, ^ P'^i't fVom BC, under pressures, somewhat lower 



