( 797 ) 



will have a double point there, in which the two branches of the 

 spinodal curve intersect each other and the line x = at an angle. 

 In this case the critical temperature of the least volatile component 

 is not changed in first approximation by small quantities of admixtures. 



With greater attraction of the most volatile component — on the 

 suppositions mentioned for m 1 <[ m <[ m, — a spinodal curve on 

 the tp-surfa.ce will have a double point. This will lie the nearer to 

 the side of the small v's, the more the attraction of the most volatile 

 component increases. With a certain value of the attraction — m=m, — 

 the spinodal curve reaches the line v = b with a double point, with 

 greater attraction the spinodal curve will proceed from x = on the 

 ^-surface with decreasing T, and touch the line v=b at T=7)- m . 

 Oji the suppositions mentioned for />22m/^iim <C 16 /ai the contact with 

 the line v — b will here take place at temperatures ]> 7/- 2 , for 

 622M/&HM ]> 16 /ai at ^ 7< C ^fcsj so (na t m tne latter case the spinodal 

 curve comes first into contact with the line x = l. 



In the first case (^22\i/^nm<C 7»i> a P'ait W *M come from x = 

 and at lower T, whereas for larger m a branch plait directed to tlie 

 side x = 1 may develoj) : if m <^ m 2 it will be united through an 

 homogeneous double plaitpoint (Korteweg, Arckiv. Neerl. 24 (1891)), 

 with a plait coming from v = b to a plait that crosses from one side 

 to the other, if m ^> m, it will pass into such a plait by contact 

 with v = b. 



In the second case the plait which becomes from x = will 

 again united with on 3 coming from v = b for smaller m ; for larger m 

 a branch plait will have developed before this union takes place 

 or before the spinodal curve touches the line v = b. 



The shape of the spinodal curve for these cases with always 

 greater attraction of the most volatile component, where we shall 

 have to consider three phase equilibria, need not be discussed for 

 the present, as they do not belong to the case of a component with 

 feeble attraction l ). 



For some values of ^om/^um table I gives the values <Z22m/<Ziim = m\ 

 calculated from the equations (2) and (3). If we compare with this 

 the values of (Z2224A&11M for which T/ cm = Tk\ (§ 6) we see that they 

 really lie between those calculated here. 



The shape of the spinodal curves for a case, in which m l <^m<^m. 1 , 

 has been represented on plate II, for the ^-surface of the unity of 

 weight (cf. § 2), with the relations and data assumed in § 2, 

 except that a„ a n = 0.00049 (or a 22 M/«iiM = 0.00196). 



] ) Cf. moreover Van Laar, Arch. Teyler (2) 10 (1906), These Proc. Sept. "06 

 p. 226. 



