( 74 ) 



3 and 4 arc unstable coexisting equilibrium, and 5 is metastable. 

 In this case of three phase pressure the second component occurs 

 in the vapour in a greater measure than in the two liquids, in con- 

 nection with the circumstances which give rise to this figure, viz. 

 that the second component has higher value of b and lower 7\. than 

 the first. In fig. 3 Cont. II, p. II the course of the pressure is 

 represented for the vapour-liquid binodal curve for this case. 



With continued rise of the degree of q the p-curve, which entirely 

 deviates from the shape of a simple isotherm for the last chosen 

 values of q, must return to such a simple shape without abrupt 

 changes. Tims the existence of 5 branches ceases when the q-Y\ne 

 passes through P,. The branches c, d and e have then decreasing 

 pressure with increasing volume. Only there is then a point where 



— and — - is equal to on this descending branch. But with still 



dVg dl'' 2 ,/ 



higher value of q also this particularity has vanished, and we ap- 

 proach to the usual shape of an isotherm. Already beforehand the g-line 



d*ip 

 which above touches — = 0, was not found to run back to larger 



dw" 1 



volumes in the unstable branch d '). 



If we increase the temperature to 7'/,., a new plaitpoint P, makes 

 its appearance at x = l and v = («jk) s . With further increase of the 

 temperature the characters of the two realisable plaitpoints P, and 

 P begin to approach to each other. In fig. 17 the closed binodal 

 curve belongs to P v Above a certain temperature, which I called 

 transformation temperature (These Proc. March 1905), this closed 

 binodal curve passes to P 3 . At this transformation temperature the 

 pairs of points |? and y have coincided on the spinodal curve in 



d*v 



tiff 17 and two branches of the binodal curve touch, and — 



° ax' 



is the same for these two branches. But for further particulars I 

 refer to the already frequently cited communication. We must only 

 bear in mind that in the case treated here r J\-, <C r J\ , whereas in 

 the figure which I gave before for this transformation it was assumed 

 that Tk.,^>Ti x . Regarding the properties of the binodal curve we 

 may then speak of a principal plait and of a branch plait. At much 

 higher T, P, and P. 2 have coincided, and the binodal curve has 

 become a normal simple line. {To be continued). 



!) Strictly speaking the change of the ^-line with increasing value of q is not 

 a moving away from and then a return to the shape of an isotherm. It must be 

 regarded as a progressive development, which proceeds in the same sense. To the 

 last 7-line belongs then also the infinitely large pressure along the line v = b. 

 This portion is. however, not necessary for the description of the binodal curve, 

 at least when the plaitpoint l\ exists. 



(June 21, 1907), 



