190 



Dr. Kuenen on the Critical Phenomena of 



curve, where the critical temperature is lowest*. In B the 

 maximum-curve meets the plaitpoint-curve. 



36. In the part C 2 B the relative position of plaitpoint- 

 curve and border-curves is like fig. 8. P lies in the direction 

 we called beyond R, and the border- curves touch the plait- 

 point-curve on its right side. The mixtures having their 

 plaitpoint between C 2 and B, i. e. containing less than 0*2 C 2 H 6 , 

 therefore must have retrograde condensation of the first kind 

 (r.c. I.) between the temperatures t? and t-R. 



37. In the part C^A the curves are situated as in fig. 9. 

 The border- curves lie on the left-hand side, but the plait- 

 Fig. 9. 



point-curve falls. P lies beyond R. The mixtures having 

 their plaitpoint here, i. e. containing more than 0*5 C 2 H 6 , 

 must also have r.c. I. between t? and £ E . 



Fig. 10. 



38. The part BA, however, fulfils the condition for tbe 

 existence of r.c. II., as is shown in fig. 10 (vid. § 6) . The plait- 



* The existence of a singular point in A was suggested to me by the 

 experimental curves (fig. 2, vid. § 42). Professor van der Waals, to whom 

 I showed my experimental results, told me that he has theoretical 



