(37) 



RT (|/a^-^.ra)> RT «' 



{if + x)\ 



v(l — V,) v^ v(l — co) v^ 



This becomes on account of «" = 26i?7'„ (see above) and ^/To^=r: 



RT, { X ] 



P = —r-^ ^ 2a) (y + .rf . 



o (1 — Ct) ) 



Let us express p in the critical pressure p^. (As, namely, the 



pressure p, corresponding to T^ {v = b) is evidently = co, p cannot 



RT, T, 16 2 RT, 



be expressed m p,). As /;, = '/, —- ^nd~ = — (p\p, = ~—^ if\ 



hence — when we put 



P 



— := n: 



Pi 



27 to 



2 y' 



-2io{<p-]-.vy'] (3) 



1— O) 



This equation may be used, when t is already known from {'lb) 

 If this value is, however, substituted, we get: 



27 a>=' r "1 



2x {{-w) 4- 2 {<p^.vy {l-oyy - {<fi + xy (l-a>) , 



jr = 



(f^ 1 — O) 



i. e. 



27 to' 



Tg = 



<fi^ 1 — O) 



2x {l-x) + (^-f-.r)' (1— to) (1— 2to) 



(3a) 



4. Better than descriptions and calculations the adjoined figures 

 1 — 4 represent the different relations which may present themselves 

 in the discussion of {lb) and {2b), combined with 3 or {Za). We 

 shall therefore confine ourselves in the following to what is strictly 

 indispensable. 



Two principal types occur, according as g) <^ 1,43 or > 1,43. 

 Fig. 1 with ip=il is a representative of the one type, fig. 2 with 

 (f=z2oi the other. The transition case ip = 1,43 is represented in 

 fig. 4. 



a. Description of the case <p = l (fig. 1 and la). 



There are two plaitpoint curves, one of which extending from 

 Co to C\, the other from C\ to A. The latter, however, may only 

 be realized down to a point between C^ and R^, where it is touched 

 by the spinodal line t = 0,63 ^). 



1) See KoRTEWEG, 1. c. p. 305 (fig. 12) and plate Fi to F^. (The plaitpoint ; has 

 already disappeared in the limiting line t' = ö in our case). Ri is a so-called point 

 de plissement double heterogene. Gf. also van der Waals, These Proc. V, 310, 

 Oct. 25, 1902. 



