( > 



discussed in a following com inimical ion 'cf. X . 96cFebr. '07, p. 660 

 footnote 1 ). 



In Fig. 2 the course of the plait has been schematically repre- 

 sented for a temperature between the barotropic plaitpoinl temperature 



and the critical temperature of the first component. The 



curves denote the pressure curves, the curve the spinodal 



curve, the continuous curve the connode. The straight line AB i- 

 the tangent chord joining the coexisting phases A and l>, CD is the 

 barotropic tangent chord Comm. 966). 



§ 3. Limited misclbility of two gases. For mixtures where as in 

 fig. 2 a plait «riving rise to phases separated by a meniscus which 

 coexist in pair-, represented in the figure e.g. by A and J>. while 

 mixtures in intermediate concentrations are not stable, extends on 

 the ^/-surface from the side of the small us at temperatures above 

 the critical temperature of the least volatile component, we shall 

 call not only the phase B a ga- phase, for which ir i- a matter of 

 course, but also the other .1: -<> the latter ma\ be called a second 

 gas />/"/«■. and we may speak of equilibria between two gaé 

 mixtures at those temperatures. That there i- every reason to do 

 so in the case treated in § 2 appear- already from tin-, that the 

 reduced temperature of the phase .1. calculated with the critical 

 temperature of the unsplit mixture with the concentration of J. i- 

 so high that already through its whole character the phase must 

 immediately make the impression of a gas phase so a second one , 



The shape of the //-lines in fig. 2 shows further, how the two 

 coexisting gas phases may he obtained by isopiestic and isothermic 

 mixing, in which nothing would indicate a transition to the liquid 

 state, from the gas phase- M and N of the simple substances 



We shall explain in the following § that it is really in accordance 

 with the distinction between gas state and liquid state for binary 

 mixtures in general, when we call ,1 a second gas phase. 



\ 4. Distinction betioeen gas ami liquid state for binary mixtures. 

 It is true that since the continuity of the ga< and the liquid state 

 of aggregation has heen ascertained, it may he -aid with a certain 

 degree of justice that it is no longer possible to draw the line between 

 the two states, but when in the definition of what is to be under- 

 stood by liquid and what by gas we wish properly to exj 

 the difference and the continuity in the character of the hetero- 

 geneous region and the homogeneous region and to preclude con- 



l j Gf. footnote 1 p. 792. 



