( 329 ) 



we have assumed as possible among others in the course of the 



isobars. 



When we take into account mixtures of water and other substances, 



we find this frequently to be the case. Thus for water and ether 



3 

 n is about 5 and ( 7/,),.,/, (;/ . = about - ( 7 '/,)„.,„,.,.. For water and CO 



4 a 



n '■ = 2,5 and — — = - . For water and nitrogen n = I,t> and 



//,, 638 -/•,_ 



1 

 much smaller than . But it still remains an open question in how 



n 



far our theory may be applied in unmodified form for mixtures of 

 which one of the components is water, a substance which behaves 

 so abnormally. In any case it is only by way of exception that 

 points of the ellipse lying on the left of the diagonal, are of practical 

 importance. If we now proceed to consider points right of the dia- 

 gonal we mention in the lirst place the point in which the ellipse 

 is cut by a line from 0', and for which tg<p = n. For this point 



'/'/.-.. 



" = J. ror all (he points for which tg (p lies between rv and u 



2% <C 1\ ■ ^ ul f° l ' l >oinls fc> r vvhich tg<p<^?i, 7/„ > 7/,. So mix- 

 tures of substances for which the substance with the larger molecule 

 has also the higher critical temperature are represented by those 

 points of the ellipse for which tg(p<^n, whereas, it' tg <p = 1, we 

 have the case that the critical pressures are the same. For this value 



of - : is equal to 3 . So the points for which ' <^ 1 reprc- 



Ph 1 4- e, 1 + e, 



sent mixtures for which the substance with the larger molocule has 

 not only higher critical temperature but also higher critical pressure. 

 .Such lines intersect the ellipse in points in which both *, and s, is 



negative, and as it is required tor non-intersection of = and 



das* 



— that these quantities are positive, and lie even bevond the 



i/r' 2 



line FQ, the ride would follow that for mixtures of substances for 

 which the substance with the larger molecule has the greater critical 

 pressure three-phase-pressure must occur. If experience should refute 

 this, i.e. if it should appear that for mixtures of such substances 

 absence of three-phase-pressure can be found, we should be induced 

 to put the question : Is perhaps in some cases 



possible; then in the equation ((f) viz.: 



