188 Dr. Kuenen on the Critical Phenomena of 



the pairs of coexisting phases being parallel to the v-axis. 

 The lines on both sides of the maximum line will be turned 

 in opposite directions (with a minimum the direction in which 

 the lines turn is the opposite of what it is here). But the 

 angles of the lines are very small in the case of C 2 H 6 and 

 N 2 0. On the right-hand plait the lines differ more: the 

 increase of pressure is accordingly larger on that side of 

 the surface. In the figure the turning of the lines had to be 

 exaggerated in order to show their direction. 



31. The critical phenomena of the mixtures were much 

 simpler than I expected to find them. All the mixtures 

 showed normal condensation up to the critical point, and 

 a difference between plaitpoint temperature and critical tem- 

 perature could not be determined with any certainty* The 

 probable cause of this disagreement I shall refer to after 

 having deduced more completely the theoretical consequences 

 of the experimental results laid down in fig. >2 ; and figs. 3 ; 4, 5 

 (vid. §§ 43-46). 



Theoretical Conclusions to be drawn from the Experimental 



Curves. 



32. A. Maximum- Curve.- — It may be proved that, the border- 

 curve of a mixture for which the pressure becomes a maximum 

 touches the maximum-curve with both its branches. This is 

 represented in fig. 6. In every point of the maximum-curve 



Fiff. 6. 



~b order, cur we. 





t order cur we 



a similar meeting of three curves takes place. If the maxi- 

 mum-mixture does not change much with the temperature 

 (as we found was the case with C 2 H 6 and N 2 0), the border- 

 curve of the maximum mixture must have nearly shrunk to 

 one curve coinciding with the maximum-curve. 



33. Apparently the p-t figure is not at all convenient for 

 showing the situation of the border-curves near the maxi- 

 mum-curve. The border-curves for the mixtures situated on 



