( 651 ) 



= — -s ; . : (3) 



\ 2RT n 2 



*Pz= S (4) 



m,„ 2 Rl'm.^ 



30 3 1 oO 



^ 11 "T 



^•^.(l-.rA.) 

 1 m,, w„, 1 m'^^ 



(5) 



2RTm,, 



2 1 30 



P.-pn- = U„,---^^^+-m3„^ S^ ^).. . . (6) 



The relations (2) and (5) are the same as I have found before ■^) 

 for the special case m^^ = O, on the edge of the if'-surface, while 

 the expression for becomes the same when we put xi = or 

 .i'i-=::l. I also find again for the border curve on the /?, ?; diagram 

 of the mixtures at the temperature T to the first approximation the 

 same parabola of the fourth degree : 



The plaitpoint, i. e. the apex of this parabola, coincides to the 

 first approximation with the point prk, vric^Tk- According as the 

 factor between brackets is positive or negative this parabola is turned 

 upwards or downwards; in the first case the special mixture has a 

 minimum vapour tension, in the second a maximum vapour tension. 



The isobars. If in equation (18) I.e. p. 327 we consider x and v 

 as two variable quantities depending on each other and ]) as a 

 parameter, this equation represents the projection of the system 

 of isobars on the x, v-surface. If ?«oi ^^ere not zero this system 

 would resemble a system of isothermals with the point xtu, i^Tk 



1) Of all the coefficients m which occur here I have formerly given the expres- 

 sions in the fc's and a and (3, except of Wo2» for which the expression follows here : 



7n,, = iS'pk + -^-01 « («-I?) Tk -]- K. «' ^k' + ^11 « («-/?) vk Ti,-k,, a' Tu 

 or reduced: 



= pkV?^ « («-^) Poi + Ó «' v\, + « («-/?) v\i-«' Poll- 



2) These Proc. V, Oct. 25, 1902, p. 329. 



