177 



From this deduction it follows that the pressure increases along 

 curve hn in the direction of the arrows, tlierefore, fj-oin n towards 

 li and that on this cnrve Im neithei- a point of inaxiniuni- nor a 

 point of minimumpiessu ro occurs. 



3. The temperature is higher than the minimnm-meltingpoint 7V 

 and lower than the point of maximum-temperalure 7// of the binary 

 equilibrium F -\- L -\- G. 



In a similar way as we have 

 deduced the general case tig. J 2 (I) 

 we now find for the satnrationciirve 

 under its own vapour- press ure an 

 exphased curve, in fig. 4 a similar 

 curve is represented by the cni-ve 

 /t?i indicated by 5; the pressure in- 

 creases in the direction of the arrow, 

 consequently from n towai'ds //. 



In fig. 4 the saturationcurves 

 under their own vapour-[)ressui'e of 

 F are drawn for several tempera- 

 tures (7\ — T'J. When we take T, 

 and 7^2 lower than 7a", then a 

 point of minimum-pressure must 

 occur on the curves, indicated by 

 1 and 2. When we take T^ between 

 Tk and J"/' and 1\ between 7a 

 and 7/7, then the saturationcurves Fig. 4. 



under their own vapourpressure have a position as the curves Im 

 indicated by 4 and 5, on which no point of minimumpressure 

 occurs. At Th the saturationcurve disappears in a point H and 

 the corresponding straight vapourline in a point H^ (not drawn 

 in the figure). 



On the saturationcurve of the temperatures 7\ and T.^ we find 

 a point of jninimum-pressure m, this point has disappeared on the 

 saturationcurve of the temperature 1\ ; between tiiese two tempeiatures 

 we consequently find a temperature 1\, at which the point in coin- 

 cides with the terminating point n of the saturationcurve under its 

 own vapourpressure. As the vapour belonging to a point of minimum- 

 pressure has always the composition F, (his case occurs when the 

 liquid n can bo in equilibrium with a vapour F. As then the binary 

 equilibrium 7'' -|~ ^-^ ~1" ^'^P^^nr F can occur (his temperature 2\ 



