( BS8 ) 

 of this deviatiou 1 have construed the locus of the point for which 



— and — ^ = 0, as has been done in "Een benaderde loop voor de 

 dv dv 



plooipuntslijn van een mengsel" (Verslag der vergadering Kon. Akad., 

 27 Nov. 1897). Now we had also to take into consideration, that 

 one of the substances is abnormal. The influence of this property 

 can only be calculated in a very incomplete manner, because the 

 way in which association of the molecules takes place in such an 

 abnormal substance, is not known. In consequence the result which 

 I have obtained by this wholly approximative calculation may only 

 be accepted with great reserve. 



The locus mentioned may occur in two different forms, which 

 depend on the fact whether in the gaseous state the molecules of the 

 abnormal substance are larger or smaller than the molecules of the 

 substance with which they are mixed. If they are larger the curve 

 has a loop which hangs down as in the figure (1). That the 

 molecules of C2 He 0, C^ Hg 0, etc. are greater than that of 

 C2 Ho will not be doubted. If on the other hand the molecules 

 of the abnormal substance in the gaseous state are smaller, the loop 

 is turned upwards. To all probability, however, the molecules of 

 C H4, will be smaller than those of C2 Ho- In this case the follo- 

 wing schematical figure may make clear the probable course. 



i?v.^ 



Let A be the critical point of ethane, B that of rnethylalcohol. 

 Let EC be the pressure-curve of the three phases and C the point, 

 in which the plaitpoint-curve, originating in ^1, meets the three-phase- 



