(778 ) 
From the equation of state: 
(l+@)RT a 
IL ~—— —- 
19 
v—b v 
it is easy to derive for 7’ constant (keeping in mind that 6 = 6, + 
+ 8A 5b):3) 
dp (1—p) RT dg RT OB 26 
— 1 Ab ; ‘ 
dv (v — b)? Ov + v—b 0v a v? 
(14-8)(—Ad) 
i.e. with - Wp 
v—b 
ee BEE maan ne 2 
dn (wv —b) 148 dv 
But from the equation (2) for 3, viz. in the form (written 
OE) dk a 
Oee for pt Ie 
B 
VE 
(14) Ab 
en 
EER REI 
from which p has been eliminated, follows by logarithmical diffe- 
rentiation (7’ constant) after some reductions (see p. 36—37 loc.cit.): 
v—b Op UR (LB) (1—@) 
IER cap oe En 
b) 
dp 
By substitution in the expression for ; obtained above we get now: 
av 
dp 2a. (1-8) AT 1 
dv o® ED 1+ VBA? 
This expression passes into the ordinary one for @=O and 1. 
i ; dps tE ART 
fligisetrue taboe ss Se wevobtan — = — 
dy ©?  (v—b)? 
b referring to double-molecular quantities, a—=4a’, v—=2v’, b=2b’ 
will have to be substituted, in which the accentuated quantities now 
B ap Za. Nags & 
refer to single molecular quantities. We get then — =—, TOE 
v = 
(7) 
but a,v and 
dy' 
as we should get. | 
Let us now first examine the points D and F (fig. 1). There vb 
is small, so p large. In this we notice that the just introduced quantity 
p is the same as our former quantity g. For in (3) etc. 
ptn (148) (Ab) 
Wise 
ae 5 p. Now p=185 
(—Ab) =p was put, so also 
1) See also Arch, Teyler, lc. p. 26—27. 
