( 345 ) 
point pi, Ty. Tr is a maximum temperature, so that this curve 
lies in the third quadrant (S'O, fig. 16.) 
2e EE R Za. 
2 
; S 
P | Ja 
Je PR 
DO es ep a oe 
1 2 
76 FR i i 
b. The plartpoint curve. According to equation (27) 
ma. Aye Tir mf RT yh, T_T) 
= = Tan Pk bot aang 
PTP pi, me RT im, aT’). Bh ; mt LRT ( t) 
This curve may have all possible directions. If we ae only real 
mixtures (7 > 0), it extends only on one side of the point pr, ive namely 
that corresponding to such values that 7-7 and m? od RT m, 
have the same siens (according to equation 26’). 
With regard to the position of the plaitpoint curve we distinguish 
the following cases: 
1. m, =90. pru= pr HA (TT), hence the beginning of the 
plaitpoint curve will lie either in the direction of the vapour pressure 
23% 
