98 
| d°b 
Hin ae da? 
( ) Ses ie | 2+ 8y?+-89— Et Ot Ie den -L 
de 9 p= m, b, cn) 
db 
HAAI HBG Tene en 
1 
| a | 
d? lp. eh yi |248h? 37 dx? ze 2 l 4 8} 
fe vR | 1? -— 8h- i erm. = ) | 4- 
d°b 
abet a ge de” 
EE is es be e ‘ - 5 . (4) 
Now we arrive at a surprising result when we apply this formula 
to systems whose molecules differ much in size. Ife.g. b, is = 100 4,, 
b : 
then = becomes = 22.4 according to the well-known formula of 
ms 
Lorentz; so g = 21,4 and h= 0.776. If we further suppose k = 20, 
= 1 1 : 
so. that= Tre AT Pii pz Pho and m, = zl Cauations (1) and 
(2) become: 
dlpe of : 
Se) tae A ea BE) te oa 
at Jt m, 
de) bgn gee ee S524 2e 
Ee ee 
: 4 Ilp 
So we find /—= 1.04 for the value of / which makes (=) 
0 
ih 
equal to O for a temperature m,=4 and the supposition f= 7; 
: 5 dlp. : Sea : 
for smaller values of / ( ) is then positive at this temperature, 
AT 0) 
for larger values negative. Equation (2a) shows further that for 
values of <4 the p,z-line ends descending for the second com- 
dp : 
ponent. So aa has the same sign on both sides for /= 1.05. But 
v 
between a region of non-miscibility will be found. For with the 
values mentioned equation (3) passes into: 
d U 3 r—0 
Pip, 
( P ) = — 14 [45258504 1} + 801-1600 0 + 4237 . (8a) 
With a value of / in the neighbourhood of 1 the lefthand member 
becomes of the order 10—!; so the curve is at first concave down- 
