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possibility to make these equations serve for a determination of 
Vk » ryyv . 
— and of RT}. Reversely, however, they can serve to determine 
q 
db v d°b 
and — — 
dv 2 dv* 
another way. In consequence of the disappearance of two equations 
for the critical point, if 7» and RZ; are known in 
which might serve for the determination of k and RT), we must 
Dg 
seek two new quantities which might serve us for this purpose, to 
which the circumstance is added, that now the equality of brb 
also disappears. Hence the knowledge of the 3 quantities 7, f, and s 
is necessary for the determination of the critical data. 
I shall assume the equation of p in the simplest form, viz.: 
En RT a 
la v—b v? 
only with the addition that 5 depends on v. But I shall assume 
dependence on 7’ neither of a nor of 6. In my investigation, entitled : 
“Quasi association” it has been demonstrated that such a dependence 
on 7’ cannot serve to account for the differences with the experiment, 
but that only the hypothesis of association can effect this. This 
removes the necessity of the assumption that « and 6 should be 
temperature functions. But of course this does not refute the possi- 
bility for such a dependence. Here I will investigate, however, in 
how far the results, obtained on the most simple suppositions, accord 
with the experiment, and not introduce again an unknown dependence, 
e.g. of 5 with 7, which would, of course, render the derivation of 
a definite numerical value, impossible. In my “Quasi association” 
I have demonstrated that it is probably not of influence for the 
critical quantities in the shape to which I then reduced them, 
; 
except for the quantity =i in a slight degree. The influence 
of quasi association on the value of the critical quantities being so 
slight, I shall neglect the quasi association for the sake of simplicity 
in the derivation of the relations which exist between the critical 
quantities, either accurate or by approximation. I shall only calculate 
at the end the extent of the deviations which are the consequence 
of this association. 
Differentiating the equation for p with respect to 7, keeping v 
re ind =| R P dp RP a 
‘onstant, we =a | or Se en oe er as 
constan N in RI ), Eh 4 eN I ” and as 
