( 608 ) 
d; d, 
tigation, in what way the lines - = Oand = = 0 get quite detached 
Hij U 
in this case. For this purpose we must ascertain what the relative 
position of these two curves will be at the temperature, at which 
da db... i . 
a i ee just for «,, and for which, therefore, fig. 4 holds. 
& U 
Now slightly on the right of z,, where 5 has very small values 
without a approaching to zero, the critical temperature is very higb, 
d 
so the two branches of 5 = 0 well certainly still exist on the right 
wD 
of z,. But this curve will be closed towards the righthand side, ie. 
passing from x, to the right we shall first have mixtures which are 
below their critical temperature at the temperature considered, then 
mixtures which are already above it, and still further to the right 
we may sometimes meet with mixtures which are again below their 
critical temperature, sometimes not. 
6. It is very easy to prove this on the supposition b,, = 4 (b, + 6,). 
In this supposition we can give a very simple construction for the 
mixture with minimum critical temperature. Let the curve on which 
A lies (fig. 5) represent the values of a, the right line BD the 
Fig. 5. 
values of 6, then: 
a 
— bt 
tg ABC — —tg DBC 
b 
in the point A. 
EN a . . . . a . C . 
As tg DBC is constant, ty ABC is minimum if ; is minimum ; 
hence we find the mixture with minimum critical temperature by 
tracing a tangent to the curve from B. For this point of contact: 
27 db 
ga ln MRT», Tre 
de JC 8 da 
