975 
the second way, it might have been maintained unchanged for-all 
normal substances, at least over a large part of the whole region. 
; \ p Di < 4 : 
The meaning of equation = —— is of course this 
Va an by \ 
Dim Dam 
that eg. for the reduced volume, which in the system in which 
b 
a . 2 q . 
j = 4 is-put equal-to »,, », Lt must be taken in the system, 
lim 
fl b, 
where = ———— — 
bim 
and the reduced volume is then equal to 1. But in the system in 
which f=7 this volume would have the value of 2 in critical 
measure. That the reduced volume is found 2 times larger is due 
to this that we have divided by a 2 times smaller factor. 
Hence the different a, m, » surfaces for substances, for which 
. Thus the critical volume is equal to 30,, if f= 4 
b 
_ might differ, do not cover each other, but they can be made 
lim 
to overlap for the greater part, almost entirely, if we divide the 
b, 
value of » by Van 
lim 
Then, however, the border lines, the loci of the coexisting vapour 
and liquid phases have not been made to cover each other. Not 
even by approximation, for this locus. which is determined by 
ve 
WONG ee), fr dv, 
Ui 
also requires- the knowledge of the properties for smaller volumes, 
and will, therefore, also demand the knowledge of presence or 
absence of quasi-association, but especially the knowledge of the 
b ae: . 
course of ok But this will be discussed later. 
g 
The cause of the circumstance that the above mentioned properties 
only hold by approximation is clearly to be seen, if it is borne in 
b Ann 
mind that the quantity : in the form found for the equation of state : 
Ig: 
bg 
= ee 3 bim Peg A het : EE Ne Ray, 
yp? by bg ö Va 
b lin blm 
