( 485 ) 



Fis. 1 



Fii; 1 liolds U)v llic case th;i( the whole of the thrcc-phasc- 

 ciirve lies imdei- lh(^ |)lait|>(»iiit-eui'\-e. e <\ <\. c^(/ is the eiii-vc of the 

 sohitions saturated with solid / j ; >' (\ <'.. c, (/ is the curve of the 

 vapours coexisting- with these saturated sohdious. lioth tliese curves 

 terminate in the point r/, \\\e melting point of />. The hatched streak 

 e e^ (\e^(l c\c^c\ c first ascends coming from lower temperatures: it 

 reaches a maximum, and then descends again. 



The curve a a, a„ a^ a, a, h is the apparent ontline of the p-A'-t- 

 surface on the />-,r-plane, or the JAcui-ve, ^/ r/^ ^/„ ^/, A was the apparent 

 outline of the y>-,r-/-surface on the 7V/'-plane or the //-curve. 



As has been proved Iw van dek Waals the curves (j e and rf 

 are two parts of one continuous curve with an intervening piece 

 which is part I v not realisable, and with two vertical tangents. 



Fig. 2 represents the case, that the ihi-ee-phase-curve cuts the 

 plaitpoint-curve. 



32* 



